570 PHYSETEBID^. 



Family PHYSETERID^E. 



No functional teeth in the upper jaw. Teeth in lower jaw 

 varying in number, sometimes only one or two on each side. 

 Bones of cranium rising into a crest behind the nares. Pterygoid 

 bones thick, produced backwards, and not involuted to form the 

 outer wall of the post-palatal air-sinuses. Transverse processes 

 of the arches of the dorsal vertebrae, to which the tubercles of the 

 ribs are attached, ceasing abruptly near the posterior end of the 

 series, and replaced by other processes at a lower level from the 

 bodies of the vertebrae, the latter processes homologous anteriorly 

 with the heads of the ribs, and posteriorly with the transverse 

 processes of the lumbar vertebras. (In Physeter both processes are 

 found in the same vertebra in the region of transition.) 



All the members of this family are oceanic, and all, so far as is 

 known, subsist mainly on Cephalopoda (cuttle-fishes). Besides 

 the sperm-whales, which form the subfamily Physeterince, and have, 

 in each mandibular ramus, several teeth set, not in distinct alveoli, 

 but in a long groove imperfectly divided by partial septa, the 

 present family contains the ziphioid whales, or subfamily Ziphiince, 

 in which only one or two teeth are functionally developed in each 

 ramus of the mandible. Members of the first subfamily alone are 

 known from the Indian seas, though there can be little if any 

 doubt that some representatives of the Ziphiince, several of which 

 inhabit the Indian Ocean, occur near the coasts of British India. 



Only two genera of sperm-whales are known ; both are Indian, 

 and they are easily distinguished thus : 



Head very large ; lower teeth 20 to 2o on each side PHYSETEK. 



Head moderate ; lower teeth 9 to 13 on each side COGIA. 



Genus PHYSETER, Linn. (1766). 

 Syn. Catodon, Artedi. 



Teeth of the upper jaw rudimentary, simply imbedded in the 

 gum. Lower teeth 20-25 on each side, stout, conical, recurved, 

 pointed until worn, and without enamel. Upper surface of the 

 skull formed of a high semicircular crest, with a deep hollow in 

 front ; from the bottom of this hollow the elongate rostrum pro- 

 trudes. Lower jaw very long, the symphysis half as long as the 

 jaw itself. 



Vertebra?: C. 7, D. 11, L. 8, C. 24. Atlas free, the other cer- 

 vicals united. 



Head about one third the length of the body (| total length), 

 high, subcylindrical, ending abruptly in front, as if truncated. 

 Blowhole single, longitudinal, and at the left side of the upper 

 anterior extremity of the huge muzzle. The mouth opens beneath 

 the muzzle, and some distance short of the end. Pectoral limbs 



