PRODELPHINUS L0NGIR9STRIS. 75 



PRODELPHINUS LONGIROSTRIS (Gray). 



Delphinus loiif/irostns, Gray, Spic. Zool., 182S, ^i. 1. 

 Delphhius microps, Gray, Zool. Ere. & Terr., 1846, p. 42, pi. 25. 

 Delphinus (dope, Gray, Cat. Get. Brit. Mils., 1850, p. 118. 

 Dtlphinus sttfuorhynehm, Gray, Cat. Seals and Whales, 18GG, p. 39G. 



This species is distiugiiishable from those of the same genus, which 

 we have already considered, by the small size of the cranium as com- 

 pared with the beak. In the Characters and Divisions, Professor Flower 

 places the four names given in the foregoing synonymy in one of his 

 sections of Clymcnla. In the List he unites stenorhynchus with lonr/i- 

 rostris, and holds alo2)e and microps as distinct species. Of the latter, 

 however, he remarks that it is "probably the same as the next {P. 

 long i rostris).'^ 



To the union of stenorhynchus aud longirostrisl subscribe with little 

 hesitation. Furthermore, the specific identity of stenorhynchus and 

 microps does not appear to me very doubtful. The tyi)e of microps is, 

 however, somewhat smaller than the txpaot stenorhynchus, though both 

 skulls seem to be of the same age. The iutermaxillse are a little nar- 

 lowed in front of the "triangle" in the former species but; not in the 

 latter. The beak is relatively longest and narrowest in stenorhynchus. 

 On the other hand, in the remaining proportions the two skulls arc alike, 

 and the teeth are equally numerous and similar in form; the pterygoid 

 bones are alike in form, having flat sides aud a very sharp keel. The 

 diflerence in the proportional width of the intermaxilhe at the middle 

 of the beak is due to the partial absorption of these bones in P. steno- 

 rhynchus. 



The corouoid process of the mandible is strongly developed in both 

 skulls. The roots of the teeth in P. stenorhynchus are flattened, a little 

 thickened, and imperforate. 



If Delphinus alope is to be kept separate it must be because of its rela- 

 tively broader beak and keeled mandibular symphysis. There is, how- 

 ever, in the collection of the National Museum, a skull. No. 211G8, which 

 is intermediate in form between alope and longirostris, and binds these 

 two species together. The beak is broader than in longirosfris or 

 microps but narrower than in alope, and the symphysis mandibuli is more 

 strongly keeled than in the two former species, but less than in alope. 

 The skull is nearly as large as that of stenorhynchus (see table of meas- 

 urements, page 7G). 



The specimens described by Dr. Liitken in his recent work,* under 

 the name of ^'■Prodelphinus alope,''^ are certainly not the Delphinus alope 

 of Gray (=P. longirostris Gray). On the other hand, the skeleton de- 

 scribed as "P. longirostris (Schl.) "does, I believe, belong to the species 

 under consideration. 



* Liitken, K. Daiiske Vidensk. Selsk., Skr., Gtli Raekke, v, pt. 1, 188'J, pp. 43-47, 



