292 J O H N CAMERON CONCLUSIONS 1. The pituitarl\.-basion-nasioii angle is an index of cranial flexion. 2. It does not exist in lower mammals. 3. It makes its first appearance in the lemurs. 4. It gradually increases in size in the anthropoid group. 5 . It reaches its maximum size in the white races, in which, therefore, cranial flexion likewise attains to its maximum. 6. It exhibits remarkable sexual consistency and also racial consistency, when studied in the American white and the American negro. 7. It evidently possesses wide ranges of variation in lower mammalian types, as in man. 8. It is evident that there is likewise a sexual factor which determines the size of the angle. 9. As regards the size of this angle, a vast evolutionary gap exists between the anthropoids and man. This is logically the space where the various ’missing links’ would have to fit in. L I T E R A T T R E CITED 1 CAMERON, JOHN192.5 The cranin facial axis of IIuxley, pt. 11. Tr. Roy. Sne. Can., third series, XIX. CORRELATION BETWEEX THE TWO ANGLES CRASIOMETRIC STTJDIES, No. 8 The present communication deals with the question as t o whether anj7 correlation exists between the two new cranial angles that were described in the sixth and seventh Craniometric Studies. It may be stated at once that an unusually favorable correlation was found to exist between these two cranial angles. The crania examined were similar in numbers to those utilized in the sixth and seventh Craniometric Studies and were divided into the same four groups-male Americaii white, female American white, male L4merican negro, a i d female American ncgro. 293 CBANIOMETEIC STUDIES The staiidartl deviations and the coefficients of variability of these angles will b e fouiid fully discussed in the sixth and serenth Craniometric Studies. A brief outline of tlie method of calculatiiig correlations was furiiished in Craniometric Rtndy, no. 1. It may be mentioned, however, that in order to obtain a really favorable correlation there should be as few numerals as possible in the -xy column. F o r instance, in the case of the female negroes four crania out of a total of tliirtyseven %-ere in the -xy column, that is t o say’, 10.8 per cent of the total number of skulls. Moreover, thi. total yielded by the -sy column was only 4.5. It was therefore manifest that a very satisfactory correlatioii was to be expected in this cranial group, a i d irideed it prored to be exceptionally high, namely, O.gO--the highest f o r all four cranial groups. Perfect correlation, it may be mentioned, is represented by 1. The next hest correlation was yielded by the female whites. In this group there were eight crania out of a total of fiftyoiie, or 15.6 p e r cent, in the -xy column. The total of the -xy column was also very small, iiamely? 6.75. The correlation 0.88-a figure was correspondingly favorable, namely, which approximated r e r y closely to that obtained in the female ncgroes. On turning to tlie male crania, it was ascertained that in the male negro group fifteen crania out of 153, o r 9.8 per cent, were in the -xy column. The total furnished by the -xy column mas 25.75. The resultant correlation, namely, 0.87, was sliglitly below that of the female iiegroes. I n the male whites twenty-two crania out of a total of 153, or 14.3 per cent, were in the -xy columii. The total of the latter was 24. 0.83. I t will thus be The correlation in this case was observed that the female crania yielded more favorable correlations than the males in both races, thus suggesting the influence of a sexual factor. It will likem-ise be recognized from table 1 that each negro type presented a more favorable correlation than the corresponding sex of the white race. + + + + + 294 TABLE 1 Showin.g t h a t the correZati,on. betwern the pituitciry-n.o.~ion-ba.~iona71.d t h e p i t ~ ~ i t a r ~ - b a s i O n - ~ ~angles a s i o n was m o w favorable in t h e femules than in tlie males of both races Female American negro, $0.90510.02106 Female American white, +0.88?0.0212 Male American negro, f0.8710.0112 Male American white, +0.8320.0167 This result suggested the possible existence of a sexual factor in determining the quality or extent of the correlation. In studying previous correlations of the skull the writer had noted the consistently favorable position occupied by the female whites, as, f o r example, in Craniometric Studies, nos. 1 and 3. This suggestion of a sexual factor was, however, rather rudely dispelled by the unfavorable position occupied by the female negroes, namely, a t the bottom of the list. A little investigation, however, suggested an explanation of this rather anomalous result. For example, in regard to the correlation between the maximum glabella-occipital length and the nasion-basion length, it was found that the results for tlie female negroes were vitiated by one single skull (cranium no. T04), and that very badly. Thus of the -xy total of 296.92, this single skull contributed the huge amount of 138.75, or nearly one-half. Therefore, by excluding this skull, it was found that the correlation for the female negroes shot up to 0.61 from 0.35--certainly an eiiormous difference. Not only so, but this raised the female iiegroes next to the female whites and well above the male whites and male negroes. Similarly, in the case of the correlation between the maximum glabella-occipital length and the nasion-pituitary length, it was ascertained that the results for the female negroes were again vitiated by a single skull, in this case cranium no. 967. The exclusion of this skull resulted in raising the female negroes from the most unfavorable position up to the same level as in the previous correlation, namely, next to the female whites and well ahove the male whiles and male negroes. It may be noted from table 2 that the female numerals tend t o group together, as also do those for the males-0.65 and 0.61, 0.44 and 0.47,0.52 and 0.50, 0.45 and 0.41,0.88 and 0.90, + + 295 C R A K l O M E T R I C STTDIES TABLE 2 I n a l l three crania.l corre2ation.y t1ku.t are exhibited i,n this table it will ha observed that t h e females, both white flnd negro, preserd t h e most faaorabk r w i l t s , thics sirggesting the existence of a sexual factor. I t m a y likewise he noted that in all cases there i~ a dejinite g a p separating t7ae females f r o m t h e 7nah 0urrr.lntion between gla.bella-necir,itnl Zcngtlt a.nd nasimt- basion length Correlntinn br17.usen glabella-oeeipital IPnyth nnd nasionpituitary l e n g t h Correlation between anglesP.A.N' Female whites, Female ncgrors, +0.05 +0.52 $0.88 +n.a +o.m Malc vhites, Male ncgroes, +0.44 +0.47 +0.45 +0.41 +0.90 f0.83 SO.87 0.83 and 0.87. There is thus evidence suggestive of the fact that in these three cranial correlatioiis there is a sexual factor a t work, resulting in more favorable correlatioiis for the female sex in both the American white and the American negro. It may be added that in all his craiiiometric work the writer has rigorously separated the male from the female crania, as he is becoming more and more conT7inced of the fact that sex plays a most important part in determining the configuration of the skull. These four craiiiometric studies are the result of research conducted in the Hamanii Museum, Western Reserve Tlniversity. The writer wishes once more to place 011 record his most cordial thanks to Prof. T. TViiigate Todd f o r the free and unrestricted use of that unique collection. 6 U M M ARY 1. A very farorable correlation was found to exist between the pituitary-nasion-basion and the pituitary-basion-nasion angles. 2. A higher degree of correlation was found t o exist in the female than in the male crania, both white aid negro. 3. The sexual factor is a most important one iii relation to cranial correlations.