SKELETON OF CARNIVORA. 497 



gain. The frontal bones form an unusually small proportion of 

 the cranial cavity : they are extensively overlapped posteriorly 

 by the parietals. Besides its superior size, the skull of Cysto- 

 phora proboscidea differs from that of the Ci/stophora cristata in 

 the form and proportions of the palatine bones, the posterior 

 borders of which present three notches ; in the relatively shorter 

 extent of the nasal processes of the premaxillaries ; in the greater 

 prominence of the antorbital processes of the maxillaries ; and the 

 absence of the depression beneath the antorbital foramen. In 

 the skull of a young Proboscis- Seal I have seen traces of a suture 

 partially dividing the orbital from the rostral part of the maxillary, 

 extending from the side of the nasal aj^ertiux into the antorbital 

 foramen : this incompletely separated part might be compared mth 

 a large lacrymal, but there is no trace of a distinct bone or of any 

 lacrymal perforation. 



In the ' Sea-Lion ' (^Otaria jiibata) the superoccipital is broader 

 and more nearly vertical than in the preceding species of Seal : the 

 basioccipital is carinate below ; the paroccipitals form an obtuse 

 angle, but are less prominent than the large mastoids. The 

 petrosals and tympanies are not expanded into a bulla ossea, but 

 send down a subcompressed smooth tuberosity : the entocarotid 

 pierces the petrosal. The pterygoids are pierced by the ecto- 

 carotids. The bony palate is very long, and remarkably concave, 

 from the bending down of its sides : its posterior border is trans- 

 versely truncate. The sagittal and occipital cristoe are singularly 

 elevated. Each frontal sends out an obtuse process near its 

 junction wdth the parietal, into the middle of the extensive tem- 

 poral fossa, and each developes large, horizontal, triangular, post- 

 orbital processes. In old males, the parietal also sends out a 

 ridge, and the great temporal muscle seems thus to have been 

 divided into three masses : there is a ridge from the inner side of 

 the parietal, dividing the middle from the anterior lobe of the 

 cerebrum, parallel with the external ridge projecting into the 

 temporal fossa. The maxillaries develope antorbital processes. 

 The nasals are short and broad, and articulate with the pre- 

 maxillaries as well as the maxillaries. 



The posterior part of the falx and the whole of the tentorium 

 are ossified. The superoccipital sinus, commencing by a common 

 aperture at the hinder extremity of tlie longitudinal sinus, diverges 

 on each side into the substance of the exoccipitals, and terminates 

 in a deep and wide fossa on the inner side of the condyle, from 

 which fossa one canal leads backward to open external to the 

 condyle, and another downward and inward to terminate in the 



VOL. II. K K 



