DELPHINLDJG. 573 



dimensions given by Owen were incorrect. Australian individuals 

 have been measured exceeding 10 feet in length. 



Distribution. Indian and Australian seas ; Cape of Good Hope ; 

 North Pacific. Probably widely distributed. Habits quite un- 

 known. The specimen obtained at Vizagapatam by Sir W. Elliot 

 was the type of P. simus, Owen. 



It has already been pointed out, that some members of the 

 Ziphiince are in all probability found in the Indian seas. They are 

 small whales, generally from 10 to 25 feet long, the best known 

 being the " Bottle-nose " (Hyperoodon rostratus) of the North 

 Atlantic. Amongst the forms probably inhabiting the seas around 

 India are Ziphius cavirostris, with a single tooth near the anterior 

 end of each mandibular ramus ; and Mesoplodon densirostris (Dio- 

 plodon sechellensis, Gray), with a large tooth on each side in the 

 middle of the lower jaw. 



Family DELPHINID^E. 



The present family comprises all porpoises and true dolphins *, 

 with the exception of a few fluviatile types. The species are much 

 more numerous than those of any other family of Cetacea. 



The size in general is moderate or small. The teeth (except in 

 the genus Grampus) are numerous in both jaws. The pterygoid 

 bones are short, thin, each involuted to form, with a process of the 

 palate-bone, the outer wall of the post-palatine air-sinus. Sym- 

 physis never much exceeding one third of the mandible in length 

 and generally much shorter. Transverse processes of the dorsal 

 vertebrae gradually transferred from the arches to the bodies of the 

 vertebra? without any sudden break ; each anterior rib attached to 

 the transverse process by the tubercle and to the body of the 

 vertebra by the head, the latter attachment lost in. the posterior 

 ribs. Sternal ribs firmly ossified. Cervical vertebra varying, the 

 first two to four generally united. 



The genera of this family tend to pass into each other, and with 

 a few exceptions are very difficult to distinguish. Professor Flower 

 (P. Z. S. 1883, p. 466) has, however, reduced the numerous genera 



^t i i i ii -i nor\ ~\JT - TI ~nr rri ^ 1~ 



much towards distinguishing the various species and eliminating 

 unnecessary synonyms. The following descriptions are in great 

 measure taken from the two works just quoted. 



Our knowledge of the Indian porpoises and dolphins is still 

 extremely imperfect. Eor the little we know, we are chiefly 



* The Dolphin of sailors, celebrated for the changes of colour it undergoes 

 when dying, is a fish (Coryphcena hippurus). 



