MESOPLODON. 71 



Upper surface of head iu front of spiracle very prominent and 

 rounded, rising abruptly from the small, distinct snout. 



Vertebra*. C. 7, D. 9, L. 10, Cd. 19 ; total 45. 



1. HYPEROODON PLANIPRONS, Flotver (1882). 



Southern Bottlenose Whale. 



This species is only known from a mutilated skull found on the 

 beach of Lewis Island, Dampier's Archipelago, and described at 

 length by Prof. Flower in the Proceedings of the Zoological 

 Society for 1882, p. 392, who figures the upper surface and the 

 side view of the skull. 



Genus IV. MESOPLODON, Gervais (1850). 



A mandible with a much compressed and pointed tooth 011 each 

 side, variously situated, but generally at some distance behind 

 the apex ; its point directed upwards and often somewhat back- 

 wards, occasionally developed to a great size. Skull not greatly 

 differing from that of Hyperoodon. Anteorbital notch not very 

 distinct. Mesethmoid cartilage ossified in adults, coalescing with 

 the surrounding bones of the rostrum, which is long and narrow. 

 Two or three anterior cervicals united, the remainder usually free. 



Vertebras. C. 7, D. 10, L. 10 or 11, Cd. 19 or 20; total 46 to 48. 



1. MESOPLODON LAYARDI, Gray, sp. (1865). 



Long-toothed. Whale. 



Mandibular tooth strongly compressed, with the apex everted, 

 and seated upon a flat strap-like base, which grows upwards, 

 backwards, and finally inwards, closing in adult males (?) over the 

 upper jaw, and sometimes actually meeting. Lateral basirostral 

 groove slight. Premaxillary foramen level with the maxillary. 



Dimensions. -Up to about fifteen feet. 

 Habitat. Nesv South Wales; Cape Seas. 



References. -Gray, B.M. Catal. Seals and Whales, p. 353, fig. 

 72 a., b. (skull and lower jaw); c. (inandibular teeth from the front); 

 Scott, Seals and Whales, p. 117. 



Note. In Mr. Krefft's MSS. occurs a notice of a Ziphiid Whale, 

 which he names M. thomsoni, but which is probably the female of 

 this species. It was stranded at Little Bay, near Sydney. 



2. MESOPLODON DENSIROSTRIS, Blainville, sp. (1817). 



Massive-toothed Whale. 



Mandibular tooth with the apex directed vertically, placed on 

 a very massive base, which is implanted in a greatly expanded 

 alveolar margin of the jaw, not found in any other species. Lateral 



