Correlations between cranial capacity and cranial length breadth and height as studied in the St. Lawrence Island Eskimo crania United States National Museum. Craniometric Studies Noкод для вставкиСкачать
CORRELATIONS BETWEEN CRANIAL CAPACITY AND CRANIAL LENGTH, BREADTH, AND HEIGHT, AS STUDIED I N THE ST. LAWRENCE ISLAND ESKIMO CRANIA, UNITED STATES NATIONAL MUSEUM CRANIOMETRIC STUDIES, No. 10 I n the ninth Craniometric Study, crania from the Greenland area were chosen as representing the eastern groups of Eskimos. In this paper the crania from St. Lawrence Island w7ill be studied as representative of the western Eskimo groups. It was decided to utilize the same numbers of crania, namely, thirty-four male (nos. 279453 to 242793) and thirty-four female (nos. 279403 to 242773). St. Lawreiice Island, it may be noted, is off the west coast of Alaska, just south of the Bering Strait. THE CRANIAL CAPACITY I n this Eskimo group the writer met with the highest cranial capacity in his experience, namely, 1810 cc., which was registered by cranium no. 279492. This is an outstanding figure even f o r a race where one normally expects a relatively high cranial capacity. The average capacity for the males of this group was 1489 cc., which was, however, lower than that found in the Greenland Eskimo male crania (1560 cc.) and the Eskimo male crania of the Royal College of Surgeons Museum (1546 cc.). The minimum for the male crania of this group was 1300 cc.--certainly, a vast reduction from the maximum. The maximum f o r the female crania, viz., 1490 cc., was below that for the Greenland Eskimo females, but decidedly above that f o r the female Eskimos of the Canadian Arctic Expedition (1), while the average capacity of 1341 cc. exactly followed suit. It is interesting, however, to note that the average cranial capacities of the St. Lawrence Island Eskimos, 269 270 JOHN CAMERON both male and female, were decidedly higher than those for the American white and the American negro, as estimated by Wingate Todd(6). These comparisons are shown in table 1. TABLE 1 The average cranial capacities of t h e St. Lawrence Island Eskimos, both male and female, are higher than those for the Hamann Museum crania, both white and negro St. Lawrence Island Eskimos (U. S. N. Museum). Hamann Museum whites.. ..................... Hamann Museum negroes ...................... Males Females 1489 P C . 1391 cc. 1350 cc. 1341 ec. 1231 ee. 1220 ce. HrdliEka's module(4) for the male crania of this Eskimo group, viz., 1542, was well above the average capacity, while in the case of the female crania it was decidedly higher-1477 compared with 1341. With such a vast range of variation of the cranial capacity in the males, it was to be expected that the standard deviation would be unusually high in these crania. This proved to be so, for it reached the high figure of 114, which was much above the corresponding amounts for the Greenland Eskimos (Craniometric Study, no. 9 ) and the Eskimo crania of the Canadian Arctic Expedition (1). The female crania exhibited the converse condition. The range of variation of the cranial capacity was in them much less, and therefore their standard deviation yielded the comparatively low figure of 71.37, which was lower than the corresponding figures for the Greenland female Eskimos and the female Eskimos of the Canadian Arctic Expedition. One should certainly expect to find in a homogeneous race like the Eskimo a lowering of the standard deviation of the various cranial measurements. This impression is confirmed by a comparison with the Hamann Museum crania, where Wingate Todd found very high standard deviations(6). This collection, as he points out, is admittedly very heterogeneous in character, representing, as it does, racial admixture from all the countries of Europe. The coefficients of variability, as usual, followed these results consistently, as table 2 shows. F o r instance, the coeffi- 271 CRANIOMETEIC STUDIES cient of variability for the St. Lawrence Island Eskimo males was relatively high, viz., 7.65, and for the females definitely lower, namely, ,5.32. TABLE 2 T h e standard deviation and coefficient of variability of cranial capacity are low in a homogeneous race like the Eskimo and comparatively high in the Hamann Museum white crania, thus suggesting racial admixture in the latter * Males Females S.D. C. of P. 71.37 91.30 85.35 126.32 5.32 6.77 6.88 10.25 St. Lawrence Island Eskimo (U. S. N. Museum) .......................... Greenland Eskimo (U. S. N. Museum). . . Canadian Arctic Expedition Eskimo.. . . . Hamann Museum white crania ... . .... . 114.00 87.65 61.78 117.58 7.65 5.61 4.48 8.45 THE CRANIAL LENGTH The range of variation of the cranial length was very extensive in the males-from a maximum of 200 mm. to a minimum of 177 mm. I n the female crania it varied from 184 mm. to 173 mm. The average cranial length was 187.5 mm. in the males, and for the females, 178.5 mm. In a dolichocephalic race like the Eskimo one would of course expect high maxima for the cranial lengths, the highest figure f o r these St. Lawrence Island males being, however, not so high as in the case of the Greenland Eskimo males. The high average length for these Eskimo crania is rendered more vivid by contrast with the low averages for the Hamann Museum white crania -181.4 mm. for the males and 173.7 mm. for the female crania (6). Though the Eskimo is generally regarded as dolichocepha h , it is interesting to note that, if one makes a survey of the various Eskimo groups, it will be observed that the cephalic length tends to diminish in a westerly direction. Moreover, it will be further noted that the cephalic index likewise varies with his geographical situation (table 3). HrdliFka has already directed attention to this fact in the Catalogue of the United States National Museum(3), where he states, “The cranial breadth, and with it the cranial (or cephalic) index, 272 J O H N CAMERON decreases gradually from the west to the east. There. is no sudden change at any geographical point. ” For instance, the cephalic index f o r the Greenland Eskimo male is given in the Catalogue as 71.5 and for the Central Eskimos, 73.8, while by the time we have reached as far west as the St. Lawrence Island group, we find that it has increased to 76.9; that is to say, there is a tendency to approximate to the brachycephaly of the Mongolian skull. TABLE 3 In the various Eskimo groups the average cranial length tends t o diminish, and the cephalic index t o increase, f r o m east to west Xdeo Females L - Craninl length C e p h n l x mm. Greenland Eskimo. ........... 190.5 Central Eskimo. ............. 189 St. Lawrence Island Eskimo. .. 187.5 Asiatic Eskimo.. ............. 186.2 braninl Zength’OephaZic inde: mm. 71.5 73.8 76.9 79.1 180.5 181.5 178.5 71.9 75.4 77.4 ..... .... The standard deviation of the cranial length in the St. Lawrence Island Eskimos was higher in the males than in the females, which was just the reverse of the condition found in the Greenland Eskimos and in the Eskimos of the Canadian Arctic Expedition. The respective figures for the two sexes were 5.30 and 3.30, and the corresponding coefficients of variation were 2.82 and 1.84. These are much lower than the standard deviations of cranial length in the American white, which were estimated by Wingate Todd(6) to be 8.19 for the male and 8.55 f o r the female crania. TABLE 4 T h e standard deviation and eoelpicient of v a r k b i l i t y of the cranial length ape low in a homogeneous rare like the Eskimo, and comparatively high in the Hamann Museum white crania, thus suggesting racial admixture in t h e latter ,Wales St. Lawrence Island Eskimos (U. S. N. Museum) ............................ Greenland Eskimos (U. S. N. Museum). .. Canadian Arctic Expedition Eskimos. ..... Hamann Museum whites.. ................ 5.30 4.50 3.66 8.19 Females 2.82 2.36 1.96 4.51 h. D . *C.ofd. 3.30 4.53 4.75 8.55 1.84 3.50 2.67 4.92 273 CRANIOMETRIC STUDIES T H E CRANIAL BREADTH The range of variation of the cranial breadth in these Rt. Lawrence Island Eskimos was from 149 mm. to 131 mm. in the males and from 140 mm. t o 128 mm. in the females. The average breadth exhibited a decided increase when compared with that of the Greenland Eskimo, the respective figures for the males being 139 mm. and 136 111111. The averages for the females were even more distinctive, namely, 135 mm. and 129.5 mm. The corresponding measurements for the Eskimos of the Canadian Arctic Expedition were 132.5 mm. in the case of the male crania and 129 mm. for the female crania. It is thus clear that the most westerly situated Eskimos, both male and female, tend to exhibit a greater cranial width than those situated in a more easterly direction. Hrdlicka (3) has already directed attention to this fact. We are thus provided with suggestive evidence regarding the point where the Eskimo branched off from his brachycephalic Mongolian ancestor, and then became more and more dolichocephalic, the farther eastward he migrated. This, however, introduces a very farreaching problem which would require a separate paper for its full discussion and elucidation. TABLE 5 The average breadth of the Eskimo skull tends to increase as one proceeds in a westerly direction through the various geographic groups Yules 7nm. Greenland Eskimo (U. S. N. Museum).. ........... Alaska Eskimo (U.8. N. Museum) ................ St. Lawrence Island Eskimo (U. S. N. Museum). ... Asiatic Eskimo (U. S. N. Museum) ............... 136 139 139 146.7 Females mm. 129.5 136 135 ... The standard deviation of breadth was higher in the St. Lawrence Island males than in the females, the respective figures being 3.52 and 2.73. The corresponding coefficients of variability, which were 2.53 and 2.002, followed these results consistently. It is thus of interest to note that the standard deviation and coefficient of variability were higher in the males than in the females in both the Greenland and the St. Lawrence Island Eskimos. It is likewise of interest 274 JOHN CAMEROX t o observe that the standard deviations and coefficients of variability in the Eskimo groups are definitely lower than in the American white, both male and female(6). TABLE 6 The stqndard deviation and coejlcient o f variability of the cranial breadth are low in a homogeneous race like the Eskimo, and comparatively high in the Eamann Museum white crania, thus suggesting racial admixture in the tatter Hazes Females 5 - T - % 3 -8 . D. St. Lawrence Island Eskimos (U. S. N. Museum) ............................ 3.52 Greenland Eskimos (U. S. N. Museum). .. 4.40 Central Eskimos (U. S. N. Museum). . . . . . 1.73 Hamann Museum white crania . . . . . . . . . . . 5.67 2.53 3.23 1.23 3.93 2.73 4.27 2.57 5.35 C . o f V. 2.002 3.30 1.86 3.84 THE CRANL4L HEIGHT The range of variation of the cranial height in these St. Lawrence Island Eskimos was from 143 mm. to 131 mm. in the males and from 139 'mm. to 124 mm. in the females. The average height in the males displayed a definite decrease when contrasted with the males of the Greenland area, the measurements being 136.5 mm. and 139.5 mm., respectively. The averages for the females were in both instances exactly the same, namely, 131.5 mm. On investigating this matter further in all the available Eskimo groups, it was noted that the reduction in cranial height was most marked in the males and practically negligible in the females. There thus appeared to be a sexual factor a t work here. These geographic and sexual differences with reference to the reduction in the height of the Eskimo skull have been previously observed by HrdliEka (3). TABLE 7 A reduction in the average basion-bregnte height of the Eskimo skull, as one proceeds from east to wcst, is well marked in the males. I t does not e d t in 8. the ease of the females. A t the figures in this table are taken from the National Museum Catalogue u. Greenland Eskimos (U. S. N. Museum). .......... Central Eskimos (U. S. N. Museum). . . . . . . . . . . . Alaska Eskimos (U. S . N. Museum). ............ St. Lawrence Island Eskimos (T.S. N. Yuseurn) . Asiatic Eskimos (U. S . N. Museum).. ........... . Males mm. Females 139.5 139.7 137.6 137 133.6 131 136.9 131.9 132 mm. ... CRANIOMETRIC STUDIES 275 The standard deviation of the cranial height of the St. Lawrence Island Eskimos was higher in the females than in the males, the figures being 3.58 and 3.23. This result was thus the converse of that found in the Greenland Eskimos. The coefficients of variability followed these figures consistently. It may be mentioned that the cranial height was the only one of the three measurements studied in this paper in which the American white exhibited a standard deviation practically the same as that of the Eskimo. Now that all three cranial dimensions have been studied, it is essential to note at this point that there is evidently an alteration in all three (with the exception of the cranial height in the females) as one proceeds in a westerly direction through the various Eskimo groups. Moreover, these alterations attain their maxima in those tribes (Greenland Eskimos) that are farthest removed geographically from the ancestral type. THE CORRELATIONS The high correlations that were obtained between capacity and length, breadth, and height in the St. Lawrence Island crania served to emphasize still further the homogeneous character of the Eskimo race. The correlation between capacity and length proved to be +0.70 for the males and 0.56 for the females. This result thus supported the assertion made by the writer in a previous paper(2) that the correlation in the Eskimo between capacity and cranial length is “rather higher in the males than in the females.” Out of six Eskimo groups studied so f a r by the writer, this correlation was decidedly higher in the males than in the females in foixr of these. In the Alaska Eskimo and the Greenland Eskimo, however, the correlations were nearly the same in both sexes, with a slight advantage in favor of the females. These results are tabulated below. Wingate Todd (6) investigated these correlations in the American white, and found them higher iii the males than in the females (table 9). + 276 J O H N CAMERON TABLE 8 1' I 1 CANADIAN ARCTIC I ~ ~ EXPEOITION A ~ * s K A ESKIMO E MUSEliN ESKIMO ESKIMO CENTRAL ~ & GREENLAND ? ~ ESKINO ESKIMO ST. ~ LAWRENCE ~ ~ ISLAND ESKIMO , This favorable correlation between capacity and cranial length in the Eskimo likewise affords support to Miss Lee's suggestion that it may be a distinctive feature of the dolichocephalic type of skull(5). The Eskimo is the only dolichocephalic race in which the writer has had the opportunity of proving the validity of this statement, so that at present he has no means of proving that it applies to all dolichocephalic races. These correlations for a homogeneous race like the Eskimo are much more favorable than the corresponding correlations for the American white, as ascertained by Wingate Todd. These are shown in table 9. TABLE 9 The correlations between cranial capacity and cranial length are high in a homogeneous racs like the Eskimo and comparatively low in the Hamann Museum white crania, both 'male and female, thus suggesting racial admixture in the latter 1 1 I I CANADIAN ARCTIC ROYAL COLLEGE OFSU&GEONS EXPEDITION ESKIMO MUSEUM ESKIMO Males, Females, I:;: + 0.72 + 0.52 CENTRA= ESKIMO 1 GREEN~IRD ESKIMO 1 1+ 1+ 1 + 0.83 0.65 I I + 0.51 0.62 1 tzzE! ST,~ A ~ R E R O E HAMARR ISLANDESKIMO , I + 0.70 + 0.56 1 ++ I 0.45 0.37 The correlation between capacity and cranial breadth likewise proved to be highly favorable in these St. Lawrence 0.83 for the males Island Eskimo crania, the fignres being and 0.67 f o r the females. The results of the present investigation show that this eorrelat,ion is somewhat variable in character in the various Eskimo groups, though an inspection + + ~ 277 CRANIOMETRIC STUDIES of table 10 shows that it is more favorable in the females than in the males in all of these groups, except one. This sexual factor was found at work in the case of the American white where Wingate Todd( 6 ) obtained a superiority of correlation in the females, as compared with the males (table 10). It may be noted in the same table that the Eskimo correlations are much higher than those found in the American white. TABLE 10 T h e correlutwn between capacity and craninl breadth tends t o be higher in t h e f c m d e s than in the males. Note t h e superiority of correlation in the Esl-imo as compared wzth t h e H a m a n n Museum while crania ALASKA ESKIMO Males, Females, + 0.65 + 0.73 ROYAL COLLEGE O F SURGEONS M U S E U M ESKIMO G RE E N L A XD ESKIMO ST. LA WR EN C E I S L A N D ES KI M O + 0.55 + 0.75 + 0.32 + 0.60 + 0.83 f 0.67 HAUNN MUSEUX WHITE + 0.46 + 0.56 The correlation between capacity and height likewise proved to be favorable in these St. Lawrence Island Eskimo crania, though to a much less extent than in the two previous correlations. The figures were 0.49 for the males and +0.32 for the females. The males thus provided the more favorable correlation. I n the other four Eskimo groups previously investigated by the writer(2) it was ascertained that the correlation between cranial capacity and cranial height exhibited greater variation than in the cases of capacitylength and capacity-breadth, but was in all, with the exception of one group, more favorable in the females than in the males. The results of the present investigation provide further evidence of the fact that this correlation is variable in character. It is of interest to record that this correlation was the only one of the three in which the American white, both male and female, exhibited more favorable results than the St. Lawrence Island Eskimo, as table 11 shows. + 278 J O H N CAMERON TABLE 11 The correlation between cranial capacity and cranial height is more favorable in the American white than in the St. Lawrence Island Eskimo, both male and female American white (Hamann Museum). . . . . . . . . . . . St. Lawrence Island Eskimo (U. S. N. Museum). Males + 0.59 + 0.49 Females + 0.60 + 0.32 CONCLUSIONS 1. The standard deviations and coefficients of variability of the cranial capacity, the cranial length, and the cranial breadth are low in a homogeneous race like the Eskimo and comparatively high in the Mamann Museum whites, thus suggesting racial admixture in the latter. The standard deviation and coefficient of variability of the cranial height practically corresponded in the two races. 2. As HrdliFka has previously pointed out, the three cranial dimensions (with the exception of the cranial height in the females) exhibit definite changes as one proceeds from east to west through the various geographic Eskimo groups. 3. The correlation between capacity and cranial length in this Eskimo group supports the writer’s previous observation that it is “rather higher in the males than in the females. ’’ 4. The correlations between capacity-length and capacitybreadth in all the Eskimo groups investigated by the writer are much higher than those for the Hamann Museum white crania. The correlation between capacity and cranial height is practically the same in both races. LITERATURE CITED 1 CAXERON, JOHN1923 Rep. Canad. Arct. Exp., XII, Pt. C, Ottawa. 2 1926 Correlations in the Eskimo crania of the Canadian Arctic Xxpedition. Trans. Rny. Sac. Can., XX. 3 Catalogue of human crania in the U. S. National Museum Collections, no. 1, 1924, Washington. 4 HRDLICKA, ALE$ 1925 Relation of the size of the head and skull to capacity in the two sexes. Am. J. Phys. Anthrop., VIII, no. 3. 5 LEE, A., AND PEARSON, K. 1901 A first study of the correlations of t h e human skull. Trans. Roy. Soc., A, XCVI. 6 TODD,T. WINGATE1923 Crania1 capacity and linear dimensions i n white and negro. Am. J. Phys. Anthrop., VI, no. 2.