214 OX THE FOSSIL BONES OF PACHYDERMATOUS QUADRUPEDS. 



so much the more interesting, as we may make application of them to 

 living ninmals to distinguish them specifically from each other, without 

 being obliged to examine their molar teeth*. At first I recognized 

 them only by the comparison of a skull of each species : now I have 

 verified them in a great number of skulls which 1 had an opportunity 

 of seeing in different cabinets of Europe, and of which Paris supplied 

 me only with eight Indian and two African. 



When these skulls are separated from their lower jaws, and made to 

 rest on their molar teeth, and on the edges of the alveoli of the tusks, 

 the zygomatic arches are nearly horizontal in both species. 



If we then consider them laterally, what is most striking is the top 

 of the head, which is almost rounded in the African Elephant, and 

 raises itself in the Indian elephant in a sort of double pyramid. 



This top or summit corresponds to the occipital arch of man and other 

 animals, and is thus elevated in the elephant merely to afford to the 

 occipital surface of the cranium a sufficient extent for a cervical liga- 

 ment, and occipital muscles proportioned to the weight of the enor- 

 mous mass which they have to sustain f. 



This difference in the form of the summits arises from the difference of 

 inclination of the frontal line, which runs much more back in the Elephant 

 of Africa, where it makes with the occipital line an angle of 115 deg. 

 than in the dephant of India, where it makes only an angle of 90 deg. 



Thence arise the principal differences of the profile, as : 



1st. The proportion of the vertical height of the head to the distance of 

 the extremity ©f the bones of the nose from the occipital crndyles, which 

 are nearly equal in the elephant of Africa, (being as 33 to 32J, and the 

 first of which is nearly one fourth greater in the elephant of India (as 

 24 to 19). 



2nd. The proportion of the distance of the edges of the alveoli of 

 the tusks from the summit, to a line which is perpendicular to it, and 

 goes from the extremity of the bones of the nose to the anterior edge 

 of the occipital foramen. The former of these lines is almost double 

 the other in the elephant of India (as 26 to 14). It is a little less than 

 one fourth longer only in the elephant of Africa (as 21 to 16). 



Besides these differences in the proportions, there are some in the 

 contours : 



1st. The forehea dof the elephant of India is hollowed into a re-entrant 

 and concave curve ; that of the African elephant is on the contrary a 

 little convex. 



2nd, The suborbital foramen is broader in the Indian elephant. In 

 the African it rather resembles a canal then a mere foramen. 



3rd. The temporal fossa is more circular in the African elephant and 

 the apophysis which separates it from the orbit, larger than in that of 

 the. Indian, where this fossa has an oval contour. 



Considered at their anterior surface these skulls present differences 

 just as well marked. 



* See the Memoirs of the Institute, class of the Sc. Math, et Phys., torn. 1 1 . 

 The plate which I give here, pi. 8, was engraved after my design, long before the 

 first impression of the preseat chapter, in the Annals of the Museum, but I gave a 

 proof of it to M. Wiedemann, professor at Brunswick, who had it copied into his 

 Archives of Zootomy, torn. ii. c. 1. pi. 1. 



j- See P.nel. Journ. de Phys., xliii, p. 47 — 60, 



