. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 596 CHEIROPTERA. .Fig. the occipital foramen, in others not so. The occipital crest is triangular, stronger in the insectivorous than in the frugivorous form. In many there is also a longitudinal crest. The face is broad. The orbits are not com- plete in either group, and the temporal fossa is large, but the zygoma in many very slender ; in some it is horizontal, in others slightly convex above. The nasal opening is very considerable; and in many whole genera, as in Rhinolopfius, in Plecotus, and several others, in
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 596 CHEIROPTERA. .Fig. the occipital foramen, in others not so. The occipital crest is triangular, stronger in the insectivorous than in the frugivorous form. In many there is also a longitudinal crest. The face is broad. The orbits are not com- plete in either group, and the temporal fossa is large, but the zygoma in many very slender ; in some it is horizontal, in others slightly convex above. The nasal opening is very considerable; and in many whole genera, as in Rhinolopfius, in Plecotus, and several others, in consequence of the intermaxillary bones not meeting each other, it is not closed at the lower part. In the genus Pteropus, and some others, as is seen in fg. 282, 283, though the intermaxillary bones meet in front, yet, as the arch is very small and narrow from before backwards, the palatine foramina unite and form a single large opening. From the extreme thinness of the cranial bones, the internal surface corresponds exactly with the external, and there is no vestige of a bony tentorium, which is so strong in many of the Carnivora. The frontal bone in the genus Pteropus presents a prominent orbitar process ; it re- sembles that of Man, and of the Quadrumunu, in the circumstance of the two portions be- coming early united. The parietals, also, unlike those of the examples just named, form but a single bone. The temporal bone has a very extensive development of its acoustic portion ; a cha- racter which is of the utmost importance to their peculiar habits, as the organ of hearing Fig. 282. Fig. 283. requires to be extensive in those animals which prey by night, and especially in such as feed upon insects and pursue them on the wing. The occipital bone is remarkable from the narrowness of its body, the transverse direction of the condyles, the short, thin, and convex form of its squamous portion, and particularly from the unparalleled proportionate size of the occipital foramen
Size: 2308px × 1083px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, booksubjectanatomy, booksubjectphysiology, booksubjectzoology
