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mal organs or with the palpebrse. It is of course well known 

 that the outer or temporal border of the orbit is deficient of 

 bone, as also a great portion of the temporal wall, and that 

 this is the case also in the rhinoceros and other true pacchy- 

 dermata, also in most of the carnassiers and the rodentia, but 

 not in the horse or in the ruminantia. In the elephant this 

 osseous deficiency in fully two-thirds of the circumference is 

 made up by a strong ligament and a fibrous mass, a sort of 

 firm boss separating the orbit from the temporal fossa ; this 

 boss admits of a slight degree of yielding or of motion back- 

 wards and outwards. On dissecting the muscles of the orbit, 

 I find, in addition to the levator palpebrse, the recti and ob- 

 liqui, a strong muscle external and parallel to the external 

 rectus or abductor oculi ; this peculiar muscle arises along 

 with the recti, proceeds forwards and outwards between the 

 external rectus and the temporal fossa, receives a nerve from 

 the sixth pair, and is inserted into this fibrous pad or boss at 

 the outer canthus of the orbit. The action of this mus- 

 cle must be to depress or retract somewhat this prominence, 

 and thus may assist in extending the sphere of vision in 

 the lateral or postero-lateral direction, so as to enable the 

 animal to see along his flank for some extent, without turning 

 round his head or neck. This provision may be the more 

 necessary to this creature, as a compensation for the restricted 

 motions of his massive head and of his short neck. Like the 

 cetaceous mammalia, the cervical vertebrae of the elephant 

 are crowded together into a short space, and the enormous 

 head appears set almost upon the chest ; he cannot, therefore, 

 perform those rapid rotatory motions of the cranium and of 

 the spine to the same extent, and with that ease and velocity 

 which we see in other animals, and which are so essential to 

 the exercise of vision in different directions. In this point 

 of view the elephant and the bird present a striking contrast ; 

 in the latter the eye-ball moves but little, and has but little 

 expression, but the cranium, articulated by a single ball and 



