DOLPHINS 291 



separate ; rostral portion of pre-maxillae broad. 

 Vertebral formula: D. 14; L. 14; C. 26 = 61. 

 Seven ribs two-headed ; five reach sternum. No 

 beak. Dorsal fin small, falcate. 



Of this genus there is really but one species, 

 Orcella brevirostris, Owen.* Head convex anteriorly. 

 Pectoral fins triangular ; dorsal fin small, falcate. 



The present species is a partly fresh-water form, and 

 occurs in the Irrawaddy 3-900 miles from the sea. 

 It is also marine. I unite the two species which 

 True regards as separate f on the authority of Mr. 

 Thomas,! wno nas recently examined material. 



The genus SAGMATJAS has the pre-maxillae 

 elevated into a crest in front of nostrils. Pterv- 



J 



goids short, scarcely or not at all touching. Teeth 

 small, 32. 



Of this genus but a single species, S. amblodon, 

 is known, and that only (as will be observed from 

 the definition) from a single skull, described by 

 the late Professor Cope. But the singular crest 

 formed by the elevation of the pre-maxillse is a 

 character which seems to be in the present state of 

 our knowledge of generic value ; it is, however, met 

 with in Phoccena. 



* Trans. Zoo!. Soc., vi., p. 24. 



t Orcella fluminalis, Gray (from Anderson's MSS.), Suppl. Cat. 

 Whales, p. So. 



+ Ann. AIus. Civ. Geneva (2), x., p. 927. 



