UHj MEMOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 



23. THE ORBITAL APERTURE. 



Orbital apertures to the number of 38 have, been measured according to Broea's instructions, 

 aud the indices computed. (See Tables XLIII, XLIV.) Of this number but 2 come within the limit 

 of Broca's class of microseine, or orbit with a low index (below S3.0). These are in skull H. 1 

 with an index of 82.92, and in skull II. 22 with an index of 81.81. There are 11 in the class of 

 mesoseme, or orbits with medium indices (88.9 to 83.0) ranging from 86.61 in skull 11. to ss.75, 

 in skull H. 13. The remaining 25 are megaseme, having high indices (89.0 and above). One orbit 

 skull II. 36, is as high as it is broad, having an index of 100, which is the maximum of this group. 



In his monograph on the orbital index Broca gives average indices for (><> tribes and divisions 

 of the human family.* Twenty-six of these are megaseme, and To this class all the American races 

 which he mentions, 15 in number, belong. Here, too, belongs our group with its average 

 index of 91.10. 



The people having an average index nearest to that of our group are the Indians of our 

 Northwest coast (91.12), while the tiatheaded Peruvians (91.50), ancient Yucatecs (91.41), modern 

 Mexicans (90.82), Patagoiiians (90.81), and North American Indians in general (90.75) are not far 

 removed. 



There are some items in the table of Broca which seem to show that antero-posterior 

 deformation of the skulls tends to decrease the orbital index. Thus in nondeformed Peruvian 

 skulls the index is 92.20, while in the deformed it is 91.50, and in ancient Mexican skulls the non- 

 deformed have an index of 93.12, the deformed an index of 90.02. These are instances of 

 deformity from intentional frontal pressure (deformation relevee). From the testimony of our 

 collection it does not appear that the accidental occipital pressure lias any effect. Of the 38 skulls 

 whose orbital measurements are recorded in the tables (XLIII, XLIV) 11 belong to the apparently 

 normal group. The average index of the latter is 91.06, which agrees closely with that of the 

 rest of the group. 



, $ 24. NASAL CHARACTERS. 



Nasal index. Forty-four skulls were in a sufficient state of preservation to allow the meas- 

 urements of the nasal orifice to be taken. As will be seen by the accompanying tables (xi.v, 

 XL vi) the average is 51.66, winch would place them in the mesorrhinian division of Broca, ?'. e., 

 where representatives of the Mongoloid races usually stand. The variation in this index is wide, 

 however, extending from leptorrhinian to extreme platyrrhiuian. 



Inferior border of nasal aperture. The inferior border of the nasal aperture, h-hancr ><>< , is of 

 a pretty high type, to judge from the meager statistics of other races to which we have access. 

 Topinard in his Elements (F anthropologist, gives six standards of comparison or classes for this 

 feature as follows: A, the sharp border; A', the slightly rounded border; B, the thick rounded 

 border; C, the border divided into two lips or sometimes three or level (plate forme-}; 1), the de- 

 pressed border, first stage of the simian groove; E, the simian groove. These six variants are 

 named in the order of their supposed morphological advancement. A being the highest and K the 

 lowest. Elsewhere | in a monograph older than his last text-book he recognizes but five types, -as 

 he had not then apparently made a distinction between A and A'. Hence, in the comparisons 

 which follow these forms are given both separately and combined. In our collection we find so 

 many grades of difference between these standards that it is often difficult to assign a specimen 

 to one or the other; our decisions are often arbitrary, still we do not, think we could improve the 

 classification if we would and in all doubtful cases we have decided with special care. 



In the Salado series among 48 nares in which the inferior borders can be studied \ve find them 

 divided as follows: Class A, 15; Class A', 13; Class B, 8; ClassC, 6; Class D, 5; Class]-;, 1. The 

 statistics given by Topinard are. in numbers only. "We have computed them in percentages (as 

 we have also computed those of the Salado series), in order that we might more easily make com- 



* Recherche sur 1'indice orbitairc, Revue d'anthropologie, Vol. iv, 187r>, pp. 616, 617. 

 t P. 800 ct seg. 



! /In iiroiitialhixinf alt^olo-totts-nasal, in Revue <l':inthr.. 1S7L', ]>p. (>:>M>:>!). Ihi Ixird'nift'-i-'u-iir tint iiuri>irx xiir IK ;', 

 et den caracterev de superiority et tTinJ'crivritc yu'il fournit, in Bull. 8o. uiitlir., 1881, pp. 1M-1'J2. 



