OCR Text |
Show 512 PROF. FLOWER ON PHOCA HISPIDA. [June 6, whereas in P. vitulina, which has not this expansion, they diverge rapidly immediately behind the symphysis. I must, however, remark that some examples of the latter species present in this region a considerable approximation to the form met with in the other members of the genus. The principal dimensions of the skull are as follow :- millims. Length of cranium, from anterior extremity of praemaxilla to occipital condyle 183 Greatest breadth across zygomata - 120 Breadth of skull in temporal fossae, just above the posterior roots of the zygomata 90 Breadth of frontals between orbits 8 Breadth of both nasals at middle of their length 9 Length of nasal 44 Breadth of occipital condyle 62 Breadth of foramen magnum 26 Height of foramen magnum 21 Greatest length of malar bone 49 Breadth between external borders of lower margin of external auditory meatus 112 Shortest distance between the auditory bullae (near their anterior ends) 33 Antero-posterior length of auditory bullae 37 Length from lower border of foramen magnum to bottom of notch in middle of hinder border of palate 100 From the last-named spot to the anterior extremity of the preemaxilla 75 From anterior extremity of praemaxilla to hinder edge of posterior molar tooth 62 From anterior extremity of praemaxilla to anterior margin of orbit 53 Breadth between inner surfaces of posterior upper molar teeth 39 Breadth between upper canines 16 Length of ramus of mandible from anterior extremity to posterior edge of condyle 117 From anterior extremity to apex of subangular process .... 101 From the top of the coronoid process to the apex of the sub-angular process 55 From the posterior edge of the condyle to the anterior edge of the masseteric depression 45 Height of ramus opposite last molar tooth 21 Length of symphysis 22 Width between apices of subangular processes 63 Width between outer edges of condyles , 100 |