PHYSETEE. 



the surface, usually in the form of a transverse, subcrescentic, 

 valvular opening, situated on the top of the head. Hand always 

 pentadactylous, the first and fifth digits however but little 

 developed. No ccecum, except in Platanista. 



Family L PHYSETERIDJE. 



No functional teeth in the upper jaw. Mandibular teeth 

 various, often few in number. Bones of the cranium raised so as 

 to form an elevated prominence behind the nostrils. Pterygoid 

 bones thick, not involuted to form the outer wall of the post- 

 palatine air-sinuses. Transverse processes of the arches of the 

 dorsal vertebra?, to which the tubercles of the ribs are attached, 

 ceasing abruptly near the end of the series, and replaced by pro- 

 cesses on the vertebra; at a much lower level, not on a line or 

 serially homologous with them, but anteriorly with the heads of 

 the ribs, posteriorly with the transverse processes of the lumbar 

 vertebrae. Costal cartilages not ossified. 



Subfamily I. PHYSETERINJE. 



Numerous teeth in the mandible which are not set in distinct 

 bony alveoli, but in a long groove imperfectly divided by partial 

 septa, and held in place by the strong fibrous gum which surrounds 

 them. No distinct lachrymal bone. Cranium strikingly asym- 

 metrical in the region of the narial apertures, in consequence of 

 the left opening greatly exceeding the right in size. 



Genus I. PHYSETER, Linnaeus (1748). 



Upper teeth of uncertain number, embedded in the gum; man- 

 dibular teeth from twenty to twenty-five in each ramus, stout, 

 conical, recurved, and pointed, without a coating of enamel. 

 Upper surface of cranium concave. Rostrum greatly elongated, 

 tapering gradually to the apex from its broad base. Mandible 

 very long and narrow, the symphysis more than half the length 

 of the ramus. Atlas free, the remaining cervical vertebra? united 

 into a single mass. Eleventh pair of ribs rudimentary. Head 

 about one-third of the length of the body, very massive, high, and 

 truncated. Nasal opening single, longitudinal, slightly to the left 

 of the median line of the head. Fore limb short, broad, and 

 truncated. Dorsal fin a mere low protuberance. 



Vertebra;. C. 7, D. 11, L. 8, Cd. 24; total 50. 



1. PHYSETER MACROCEPHALUS, Linnceus (1766). 



Sperm. Whale ; Cachalot. 



Body above very dark, occasionally black, fading gradually on 

 the sides and belly, silvery gray on the chest. 



