J 96 MEMOlllS or THE NATIONAL AGAJ>EMY OE 8CiENGES. 



^ 23. THE ORBITAL APERTUKE. 



Orbital apertures to the number of 38 have been measured accordiug to Broca's instructions, 

 and the indices computed. (See Tables XLni, xxiv.) Of this number but 2 come within the limit 

 of Broca's class of microseme, or orbit with a low index (below 83.0). These are in skull H. 1 

 with an index of 82.92, and in skull H. 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. Gl in skull H. 6 to 88.75, 

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

 skull H. 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 66 tribes and divisions 

 of the human family.* Twentj^-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 ilatheaded Peruvians (91.50), ancient Yucatecs (91.41), modern 

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

 lemoved. 



There are some items in the table of Broca. which seem to show that anteroposterior 

 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 relcve'e). From the testimony of our 

 collectiou it does not appear that the accidental occipital pressure has 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. • 



N'asal index. — Forty-four skulls were in a sufiicient state of preservation to allow the meas- 

 urements of the nasal oriHce to be taken. As wiM be seen by the ;icLomii;inying tables (XLV, 

 XL VI) the average is 51.06, which would place them in the mesorrhinian division of Broca, i. e., 

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

 however, extending from leptoi-rhinian to extreme platyrrhinian. 



Inferior border (f iiasaJ itperfxre. — The inferior border of the nasal aperture, echancrure, is of 

 a pretty high type, to .indi^r fnnii (he nicaucr statistics of other races to which we have access. 

 Topinard in his Elements irdiithropiiloijici, 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); D, 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 E the 

 lowest. Elsewhere |: in a monogra])h older than his last text-book he recognizes but five tyiies, as 

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

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

 jnany grades of difference between these standards that it is often diflflcult 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 uares in which the inferior borders can be studied we find them 

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

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

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



' Recherche siir I'incUce orbitaire. Revue d'anthropologie, Vol. iv, 1875, pp. 616, 617. 

 t P. 800 vt seq. 



I 1)11 irroijnaihiame alviolo-aous-nasal, in Revue cVanthr.. 1872, pp. 634-639. Da hordinfi'nem- th-H luirinen aiic le crane 

 et dcs caraotirea de aupiriorUe et d'inf&iorite qu'ilj'ournit, in Bull. Soc. authr., 1881, pp. 184-192. 



