Correlations between cranial capacity and cranial length breadth and height as studied in the Mongol crania United States National Museum. Craniometric Studies Noкод для вставкиСкачать
CORRELATIONS BETWEEN CRANIAL CAPACITY AND CRANIAL LENGTH, BREADTH, AND HEIGHT, A S STUDIED I N T H E MONGOL CRANIA, UNITED STATES NATIONAL MUSEUM CRANIOMETRIC STUDIES, No. 11 This paper deals with the same correlations that were considered in the ninth and tenth Craniometric Studies. It was decided to make a study of the same problem in a race closely allied to the Eskimo, namely, the Mongol. The crania all came from Urga, in Mongolia. The same numbers were utilized as in the two previous Studies, namely, thirty-four male (nos. 278794 to 278886) and thirty-four female (nos. 278913 to 278739). THE CRANIAL CAPACITY The writer was much impressed by the high maximum of 1770 cc. for the males of this group, which was higher than in all the six Eskimo groups previously studied, wjth the exception of the Central and St. Lawrence Island male crania. Some of the other male Mongolian crania registered very high capacities, so that it was not surprising to find the high average of 1555 cc. f o r the thirty-four crania. This was higher than in all the Eskimo groups, except those from the Central and Greenland areas. The minimum was actually as high as 1330 cc. The maximum capacity for the thirty-four female Mongolian crania, namely, 1590 cc., mas higher than in any of the Eskimo groups cited above, while the average of 1392 cc. was also higher than in all of these, with the exception of the Central Eskimos. The writer was therefore frankly surprised to find such high capacities for the Mongolian type of skull, which emulate the well-known high capacity of the 280 CRANIOMETRIC STUDIES 281 Xskimo skull. They were much higher than the averages for the Hamann Musenm white and negro crania, both male and female, as estimated by Wingate Todd ( 5 ) . TABLE 1 T h e average capacities of t h e crania fTom Urga, Nongolia, compared with those for the Haniann Museum white and negro cronia Mongslian crania (U. S. N. Museum). .......... Hamann Museum whites.. ...................... Hamann Museum negroes. ...................... Males Females 1555ee. 1391 ec. 1350 ec. 1392 ce. 1231 cc. 1220 ec. HrdliEka’s module(3) for the whole 114 male crania of this group, viz., 1551, was slightly below the average capacity of 1573 cc. The module in the case of the whole seventy-three female crania, viz., 1473, was well above the average capacity -1406 CC. The standard deviation of the capacity for these thirtyfour Mongolian crania was relatively high, namely, 111.44, but it was lower than in two of the six Eskimo groups mentioiled above. The standard deviation for the female crania, viz., 104.99, was lower than that f o r the males, and this also held good for d l the Eskimo groups except two. These standard deviations, however, were much lower than those for the Hamann Museum whites, where the figures were 117.58 for the males and 126.32 f o r the females. The contrast in the case of the female crania is particularly striking. It is evident, then, that the standard deviations of capacity for these Mongolian crania are on a par with those for a homogeneous race like the Eskimo, and it is therefore possible they may represent a racial type that is likewise homogeneous in charqcter. This impression gains credence when it is stated that the standard deviations f o r the other cranial measurements studied in this paper are all uniformly low, while the corresponding correlations will be show-n to be unusually favorable. As a matter of fact, in an isolated country like Mongolia, situated in the interior of a vast continent, with the most primitive means of intercommunication, one would naturally expect t o find conditions favorable for the creation of a comparatively homogeneous race. 282 JOHN CAMERON TABLE 2 The standard deviafion of cranial capacity is low i+a a homogeneous race like the Mongol and comparatively high in the Harnann Museum white crania, t h w suggesting racial admixture in the latter Mongol (U. S. N. Museum) ................... Hamann Museum whites.. .................... Ydes Females 111.44 117.58 104.99 126.32 THE CRANIAL LENGTH The range of variation of the length in these Mongolian crania was from 198 mm. to 178 mm. in the males and from 186 mm. to 163 mm. in the females. It is of significance to note that the average cranial length for the males, viz.,187 mm., was practically the same as that for the St. Lawrence Island male Eskimos (187.5 mm.). The figures for the females of the two races were also almost exactly alike, namely, 177 mm. and 178.5 mm. It is therefore of interest to note that the average length of the dolichocephalic Eskimo skull which reaches the maximum in the most easterly situated tribes (Greenland area) gradually diminishes as one proceeds westward, until in the most westerly situated tribes one can detect an approximation to the corresponding dimension of the brachycephalic Mongolian skull. It may be further noted that the maximum length for these male Mongolian crania, viz., 198 mm., almost equaled that for the St. Lawrence Island Eskimo males (200 mm.), while the maximum length for the females, viz., 186 mm., actually exceeded that for the St. Lawrence Island Eskimo females (184 mm.). TABLE 3 The average length of the dolichocephalic E s k i v o skull gradually merges, as has been pointed out b y HrdCiEka (Cat. no. 1, '27), with the corresponding dim&n of the brachycephalic Mongolian skull as one proceeds from east to west Males mm. Greenland Eskimo (U. S. N. Museum). .......... Central Eskimo (U.S. N. Museum). ............. St. Lawrence Island Eskimo (U. S. N. Museum). .. Asiatic Eskimo (U. S. N. Museum) ............ Mongol (U.S. N. Museum) ..................... 190.5 189 187.5 186.2 187 Females mm. 180.5 181.5 178.5 ..... 177 283 CRANIOMETRIC STUDIES The standard deviation of the length of these Mongolian crania was slightly lower in the males than in the females, the respective figures being 4.91 and 5.52. The coefficients of variability followed these results consistently, namely, 2.62 and 3.12. These standard deviations were closely similar to the averages for a homogeneous race like the Eskimo, and thus contrast with the high standard deviations f o r the Hamann Museum whites, 8.19 for the males and 8.55 for the females, as estimated b>-Wingate Todd( 5j. TABLE 4 The standard deviations and coefficients of variability of cranial length are low in comparatively homogeneous races like the Xslcimo and the Mongol, and relatively high in the Haniann Museum whiten, t h u s suggesting racial admixture i n the latter Females Yales St. Lawrence Island Eskimos.. ........... Greenland Eskimos. ..................... Canadian Arctic Expedition Eskimos. ..... Mongols ............................... Hamann Museum whites.. ............... G---%X? 8.o.T. 5.30 4.50 3.66 4.91 8.19 3.30 4.53 4.75 5.52 8.55 2.82 2.36 1.96 2.62 4.51 1.84 2.50 2.67 3.12 4.92 THE CRANIAL BREADTH The range of variation of the breadth in these Mongolian crania was from 152 mm. to 140 mm. in the males and from 148 mm. to 132 mm. in the females. The average was 146 mm. for the males and 140 mm. for the females. These were both definitely higher than the corresponding measurements for the six Eskimo groups previously mentioned, and therefore afford a marked contrast between the proportions of the dolichocephalic and brachycephalic types of skull. It is likewise of interest to note that the maximum breadth and the minimum breadth in the male crania were both higher than the maxima and minima for all of the six Kskimo groups. In the case of the female crania, the maximum was higher than in all of the six Eskimo groups, while the minimum was higher than in all except one. It is also significant to note that the average breadth of the Eskimo skull exhibits a gradual increase as 284 JOHN CAMERON one proceeds from east to west until its size finally approximates to that of the brachycephalic Mongol skull. TABLE 6 T h e a'verage breadth of t h e dolichoeephalic Esbimo skull gradually increases as one proceeds f r o m east to west until it finally approximates t o that of the brachycephalic Mongol skull Fem,nles Nales Greenland Eskimo (U. S. N. Museum). . . . . . . . . . . Alaska Eskimo (V. S. N. Museum). ............. St. Lawrence Island Eskimo (U. S. N. Museum). . Asiatic Eskimo (U. S. hT.Museum). ............ Mongol (U. S . N. Museum). . . . . . . . . . . . . . . . . . . . mm. mm. 136 139 129.5 156 135 139 146.7 146 ..... 140 This approximation of the average length and average breadth of the Eskimo skull to those of the Mongol type is admirably demonstrated by a study of the cephalic index. For instance, the U. S. National Museum Catalogue(2) gives the cephalic index of the Greenland Eskimo male as 71.5, which represents well-marked dolichocephaly, while it has become raised to 76.9 in the St. Lawrence Island Eskimo male. The cephalic index for the male Mongol is 81.4, according to the Catalogue. This gradual increase is shown in table 6. The same increase holds good for the female crania. TdBLE 6 T h e cephalic index of t h e doldehocephalic Eskimo skull gradually increases f r o m east t o west, until it approximates t o the broc7~ycephaZyof t h e M o n g d skull (HrdliFka, Cat. 1u). 1 , '27) Females Males 71.9 Greenland Eskimo (U. S . N. Museum). .......... 71.5 75.4 Central Eskimo (U.S. N, Museum). ............ 73.8 77.4 St. Lawrence Island Eskimo (U. 5. N. Museum). 76.9 Asiatic Eskimo (U. 5. N. Museum). ........... 79.1 .... Mongol (IT. S. N. Museum) .................. 81.4 82.4 The standard deviation of the breadth of these Mongol crania was slightly lower in the males than in the females, the respective figures being 3.17 and 4.20. The coefficients of variabiIitp followed these results consistently, namely, 2.17 and 3. These results compare favorably even with a homo- 285 CRANIOMETRIC STUDIES geneous race like the Eskimo, and contrast with the relatively high standard deviations for the Hamanii Museum white crania, namely, 5.67 for the males and 5.35 for the females, as estimated by Wingate Todd(5). TABLE 7 T h e standard deviations of cranial breadth f o r both sexcs are low in comparatively homogeneous races like t h e Xongol and Eskimo and relatively high in the Haniann MiMeuw while crania, thus suggesting racial admixture in the latter Females 3fQZfX St. Lawrence Island Eskimos (IT. S.N. Museum). 3.52 Greenland Eskimos (U. S. N. Museum).. . . . . . . . Central Eskimos (U. S. W. Museum). ........... Mongols (U. S. N. Museum). ................. Hamaun Museum white crania.. ................ 2.73 4.27 2.57 4.20 5.35 4.40 1.i3 3.17 5.6i THE CRANIAL HEIGHT The average height of these Mongolian crania exhibited a marked decrease when compared with that of the varions Eskimo groups, the figures for the males being 131 mm. and for thc females 125 mm. The range of variation was from 140 mm. to 118 m. in the case of the male crania, and from 135 mm. to 117 mm. in the females. Hrdli6ka( 2) has directed attention to a gradual reduction in the average height of the dolichocephalic Eskimo skull, particularly in the males, as one proceeds from east to west through the racial groups. It is significant to note that this ‘geographic reduction ’ tends ultimately to approximate to the average height of the brachycephalic Mongol skull. TABLE 8 T h e average height of t h e doliehocephalic Eskimo skull gradually diminishes from east to west, particularly in t h e mules, until it finally approximates t o that of the brachycephalic Mongol skull Males mm. Greenland Eskimo (U. S. AT. Museum) . . . . . . . . . . . . . Central Eskimo (U. S. N. Museum). .............. Alaska Eskimo (U. S. N. Museum). . . . . . . . . . . . . . . . St. Lawrence Island Eskimo (U. S. N. Museum ..... Asiatic Eskimo (U. S. N. Museum). Mongol (U. S. N. Museum). ..................... .............. 139.5 139.7 137.6 137 133.6 131 286 J O H N CAMERON The standard deviation of the height of these Mongol crania was ascertained to be higher in the males than in the females, the respective figures being 5.63 and 4.22. The coefficients of variability followed these results consistently4.29 and 3.37. These results are, on the whole, rather higher than those obtained in the Eskimo crania. Now that the three cranial dimensions have been studied, it is important to note at this point that the alterations in all three, which have been previously detected as one proceeds from east to west through the various Eskimo groups, finally tend to approximate to the corresponding dimensions of the Mongol skull. This fact is of great morphological importance, f o r it demonstrates the transition from the dolichocephalic to the brachycephalic type of skull or vice versa. It likewise demonstrates the racial affinity that exists between the Eskimo and the Mongol. THE CORRELATIONS The correlation between capacity and length in these sixtpeight Mongol skulls was found to be unusually favorable in both sexes, with a slight advantage in the case of the females. The figures were 0.76 and 0.73. The writer has already( 1) obtained relatively high degrees of correlation in the Eskimo skull, as compared, for example, with the Hamann Museum white and negro crania. His Eskimo results therefore afforded support to Miss Lee’s suggestion(4) that a high correlation between cranial capacity and cranial length was a distinctive feature of the dolichocephalic type of skull. Conversely, one would of course have expected not so favorable a correlation between capacity and length in the brachycephalic type of skull, but this is not borne out by the results obtained in these markedly brachycephalic Mongol crania. Therefore, it is evident that one can obtain highly favorable correlations between capacity and length in both the dolichocephalic and the brachycephalic types of crania. The author begs t o offer another explanation. He has already pointed out that the Eskimo and Mongol crania which have been re- + + 287 CRhNIOiVIETRIC STUDIES ported upon in the present group of craniometric studies represent individuals belonging to two comparatively homogeneous races. This conviction gains support when one compares the low standard deviations and high correlations obtained in these races with those yielded by the heterogeneous material represented by the Hamann Museum white crania(5). From this viewpoint, then, a high correlation would signify homogeneity of race rather than representing a characteristic feature of a special type of skull. The correlations between cranial capacity and cranial length in these three racial groups are represented in table 9. T4BLE 9 The correlation between cra,nial capacity and cranial length in both sexes is high in comparatively homogeneous races like the Eskimo and Mongol, and low in the Hamann Museum white crania, thus suggesting racial admixture i n the latter ST. LAWRENCE ISLAND ESKIMO, U. S. N. M. ESKIMO Males, Females, I + 0.72 + 0.52 1 + 0.83 + 0.65 + 0.70 + 0.56 MONGOL, HAXA" U. 6. N. M. MUSEUM WHITES + 0.73 + 0.76 + 0.45 + 0.37 I The correlation between capacity and breadth was likewise found to be highly favorable in these brachycephalic Mongol crania. Moreover, the figures for the two 'sexes were fairly close together, with a slight advantage in favor of the males0.72 and $- 0.64. These results are, on the whole, more favorable, and certainly much more stable for the two sexes, than in the case of the Eskimo (table 10). Again, the correlation is in this instance more in favor of the male crania, whereas in the Eskimo it tends to show more favorable results in the females. Their favorable character likewise contrasts very vividly with the corresponding correlations for the Hamann Museum white crania, as table 10 shows. Whether or not this highly favorable correlation between ca- + 288 J O H N CAMERON pacity and breadth holds good for all types of brachycephalic crania remains, of course, to be seen. TABLE 10 Note the high correlations between capacity and cranial breadth in the Eskimo and the Mongol as compared with the Hamann Museum white crania ALASKA ESKIMO Yalea, Females, ROYAL COLLEGE OBEENLSND O F SURGEONS MUSEUM ESKIMO ESKIMO + 0.65( + 0.55 + 0.73~ + 0.75 1 1 ~ ST.LAU'RENCE I S ~ ~ ESHIMO i D HAMANN ~ I XoN@oJJ WHITE I f 0.32 f 0.60 ~ + 0.83 + 0.67 1 1 I + 0.72 + 0.64 1 ~ + 0.46 + 0.56 The writer(1) has previously pointed out that in Eskimo crania the correlations between capacity-length and capacitybreadth are more favorable than that between capacity-height. The same fact holds good in another homogeneous race, such as the Mongol, where the results for capacity-height were 0.58 for the males and 0.59 f o r the females. found to be This result was thus most remarkably consistent f o r the two sexes, and therefore in striking contrast to those for the Eskimo groups, which exhibited very wide ranges of variation in the case of this correlation. It may be further noted that in both the Eskimo and the Mongol crania the correlation between capacity and height tended to be more favorable in the females than in the males. It is interesting to record that this correlation was the only one of the three in which the American white, both male and female, exhibited as favorable results as the Mongol (table 11). + + TABLE 11 T h e correlation between capacity and cranial height was as favorable in the Hamann Museum white crania as in the Mongol crania, the results being practically the same in both races Hnrnnnn Musauna white Mongol (U.S. N. X ) 0.58 0.59 Males . . . . . . . . . . . . . . . Females . . . . . _. _ ._. _ _ . . +0.60 0.59 . . + + + CRANIOMETRIC STUDIES 289 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 Mongol and comparatively high in the Hamann Museum whites, thus suggesting racial admixture in the latter. The standard deviation and coefficient of variability of the cranial height are, however, rather better in the Hamann Nuseum whites. 2. The average length, breadth, and height of the dolichocephalic Eskimo skull, as already shown by Hrdligka, gradually merge with the corresponding dimensions of the brachycephalic Mongol skull as one proceeds from east to west through the various Eskimo groups. 3. This fact is of great morphological importance, for it demonstrates the transition from the dolichocephalic to the brachycephalic type of skull, or vice versa. It likewise demonstrates the racial affinity that exists between the Eskimo and the Mongol. 4. The high correlations between capacity-length and capacity-breadth which the writer previously obtained in a homogeneous race like the Eskimo were also present in a homogeneous race, such as the Mongol. 5. Whether or not this highly favorable correlation between capacity and breadth in these Mongol skulls holds good f o r all types of brachycephalic crania remains to be seen. 6. The correlation between capacity-height is relatively low, even in comparatively homogeneous races, such as the Eskimo and the Mongol. LITERATURE CITED 1 CAMERON,JOHN1926 Correlations in the Eskimo crania of the Canadian Arctic Expedition. Trans. Roy. SOC. Can. 2 HRDLIEKA,ALES 1924 Catalogue of human crania in the U. S. National Muscum Collections, no. 1, Washington. 3 -- 1925 Relation of the size of the head and skull to capacity in the two sexes. Am. J. Phys. Anthrop., VIII, no. 3. 4 LEE,9., AND PEARSON, K. 1901 A first study of the correlation of the human skull. Trans. Eoy. Soe., A, 96. 5 TODD,T. WIXGATE 1923 Cranial capacity and linear dimensions in white and negro. Am. J. Phys. Anthrop., VI, no. 2.