NO. 2086. 



SOME MAMMALS OF THE PLEISTOCENE— HAY. 



557 



The elements from which the following table has been prepared 

 are found in Nehring's and Salensky 's papers. 



Measurements of skulls of Equus zebra in millimeters, with indices. 



Specimen. 



Basilar 

 length. 



Vertex 

 length. 



Frontal 

 width. 



Ce- 

 phalic 

 index. 



Cranial 

 length. 



Cranio- 



cephalic 



index. 



Facial 

 length. 



Facio- 



cephalic 



index. 



For. 

 mag. to 

 vomer. 



Vomer 

 to 



palate. 



800, Nehring 



1450, Nehring 



799, Nehring 



5238, Salensky 



Ill, Salensky 



446 

 451 

 492 



485 

 437 



504 

 520 

 555 

 555 

 483 



180 



184 

 205 

 187 

 201 



40.4 

 40.8 

 41.6 

 38.6 

 45.9 



161 



168 

 191 

 188 

 173 



36.1 

 37.2 

 38.8 

 38.7 

 39.6 



334 

 356 

 379 

 375 

 321 



74.9 

 78.9 

 77.0 

 77.3 

 73.4 



100 

 113 

 130 

 119 

 112 



112 



114 

 114 

 103 



Averages 



462 



523 



191 



41.4 



176 



38.1 



353 



76.3 



115 



111 



Among the skulls represented here there is a remarkable amount of 

 variation, and this appears especially in the two sets of measurements 

 furnished by Salensky. The first of these two has a skull as narrow 

 as the average of those of E. grevyi, while the second skull is as wide 

 as that of some of the asses. Indeed, this second skull resembles 

 closely the last one in the list of those of E. asinus. In case this 

 skull should be left out of the estimate as being that of an unusually 

 developed beast or as possibly not of this species, the cephalic index 

 would be 40.4, and the variation between the lowest and the highest 

 value would be less than 7.4 per cent of the mean. In other respects 

 the species, as represented, would show close conformity to its type. 



Consideration will now be given to some of the forms which pass 

 under the name of asses. Equus asinus is included, although a do- 

 mesticated animal. 



Measurements of skulls of Equus hemionus in millimeters, with indices. 



Specimens. 



Basilar 

 length. 



Vertex 

 length. 



Frontal 

 width. 



Ce- 

 phalic 

 mdex. 



Cranial 

 length. 



Cranio- 



cephalic 



index. 



Facial 

 length. 



Facio- 



cephalic 



index. 



For. 



mag. to 

 vomer. 



Vomer 

 to 



palate. 



513, Salensky 



1075, Salensky 



516, Salensky 



515, Salensky 



511, Salensky 



217, Salensky 



224, Salensky 



515, Tscherski 



427 

 445 

 436 

 465 

 463 

 468 

 469 

 472 



487 

 499 

 498 

 529 

 529 

 525 

 520 

 522 



197 



197 

 198 

 202 

 204 

 209 

 196 

 201 



46.1 

 44.2 

 45.4 

 43.4 

 44.1 

 44.6 

 41.8 

 42.7 



160 

 163 

 155 

 166 

 167 

 167 

 171 

 163 



37.5 



36.6 

 35.5 

 35.7 

 36.1 

 35.7 

 36.4 

 34.5 



338 

 343 

 341 

 374 

 368 

 361 

 358 

 364 



79.1 

 77.1 



78.2 

 80.4 

 79.5 

 77.1 

 76.3 

 75.9 



95 

 105 

 105 

 116 

 106 

 115 

 111 

 115 



122 

 112 

 113 

 110 

 120 

 103 

 128 

 110 



Averages 



456 



514 



201 



44.1 



164 



36.0 



355 



77.9 



109 



115 



A study of this table shows that there is a difference of 45 mm. 

 between the greatest basilar length and the least. This difference 

 equals less than 10 per cent of the average length. Between the 

 widest and the narrowest skull there is a difference of only 13 mm. 

 The cephalic index presents an extreme variation of about 9 per cent 

 of the average. The cranio-cephalic index shows a variation amount- 

 ing to 8.3 per cent of the mean, while the facio-cephalic index varies 

 to an amount equaling 5.8 per cent. 



