LEPTONYOHOTES — OMMATOPHOCA. 203 



placenta 2|- inches broad. As the chorion had been 

 divided in making the section through the wall of 

 the cornu, the umbilical vessels can be seen entering 

 the free surface of the placenta, which has a con- 

 voluted surface, such as I have described in the 

 placenta of Halichoerus grypus. The uterine wall, 

 especially in the placental region, is very vascular, 

 and the raucous membrane with which the non- 

 villous chorion is in contact, is not absolutely smooth, 

 but marked by very faint ridges, possibly due to the 

 hardening action of the formalin in which the uterus 

 had been preserved. The dissection was made by 

 Dr David Waterston, and the figure is reproduced 

 with his permission. 

 From the Scottish National Antarctic Expedition. 



Donor— Dr W. S. Bruce. 



5. Penis from another specimen, showing the part in relation 

 to the investing integument 8i inches long, as well 

 as the deeper end of the organ, 5 inches long. The 

 glans is 5i inches long, measured along the curve. 

 The meatus is distinct at the free end of the glans. 

 From the Scottish National Antarctic Expedition. 



Donor— Dr W. S. Bruce. 



III. OMMATOPHOCA. (Om.) 



Ommatophoca rossi, Gray, Zool. Voy. Erebus and Terror, 

 1844. 



Premaxillae do not reach nasals. Anterior nares almost 

 in vertical plane. Nasals long, ankylosed. Orbits 

 very large ; inter-orbital part of frontal bone broad, 

 not constricted behind. Malars greatly elongated: 

 marked protuberance on squamous immediately 

 behind zygoma. Hard palate slightly scooped, 

 length and greatest breadth equal or almost equal. 

 Tympanic bulla not much swollen, triangular, 

 roughened, prolonged outwards into a strong process 

 which forms the floor of external meatus extending 

 beyond its opening. Basi-occipital not perforated. 

 Pterygoids everted, oblique. Mandible with rough, 

 inverted subcondyloid process, distinct from the 



9 9 Y \ 5 g 



moderate angle. Dentition : in. ^ ^ , c. - ^ , p.c. ^ -_ : 



11 11 5 5 



crowns of post-canines relatively small, one large cusp 



with two subordinate cusps, two-fanged except first. 



