78 BULLETIN 30, UNITED STATES NA'UUNAL .MUSEUM. 



to hold good, it willaidin distill guisliing this gcniis iVoiii lAujiiiorhnnchm, 

 Prodelphiniis, Tnrsiops^ and Delphinvs, its nearest allies. 



In the skull in the National Museum the free margins of the maxilke 

 behind the notch are thinned out as in iSaffiiiatias. 1 neglected to note 

 this character in the skull in the College of Surgeons, and Van Beneden 

 and Gervais figure only the lower side of their specimen. 



The mandible of our specimen isremaikable for its extreme attenua- 

 tion anteriorly. It is bent downward and is not keeled anteriorly. In 

 Cuvier's figure of Z. i)eronii the mandible is bent downward, but is dis- 

 tinctly keeled [Oss.fossiles, 4tli ed., pi. 222, figs. 5-G). 



The scapula of L. peronii, figured by Cuvier {Oss. Joss., 4th ed., pi, 

 224, fig. 20), is, as pointed out, remarkable for its width as compared 

 with its height. The acromion and coracoid are also very large. 



The genus may be provisionally defined as follows: No dorsal fin. 

 Pterygoids apart in the median line, at least at the base. Maxilhe not 

 thickened behind the notch. 



Two species are tolerably well known, the one, L. iKronli, from the 

 South seas, and the other, L. horeaJis, from the North Pacific. They may 

 be distinguished by their coloration, as follows: 



1. Beak aud pectoral fins white L. 2>croiiii 



2. Beak and pectoral lius dark, like the back L. horealis 



\ 



tUESIO PERONII (Laccpede). 



Delphiniis peroiiii, Lac(5pcde, Hist. uat. des Cetaci^s, 1804, p. 316. 



Del2)hhnis leucorhamjihus Pcroii (MH.), fiilc Lact'i*etle, Hist. uat. des C6tac6s, 1804, 



p. 31(). 

 LeucorhampliHn pcionti, Lilljcborg, Upsala Umv. Arsskrift, 18G1, p. 5. 



Neither Lacepede nor Desmarest (IMammalogie, p. 517) seems to have 

 suspected that P eron's Danphhi leueorhamphe was without dorsal fin, but 

 Cuvier,* having obtained a skin from India through Dussumier, in 

 which the dorsal was absent, while the colors corresponded to those of 

 Peron's dolphin, concludes that the latter was finless. He identifies 

 his specimen with the D. pcronii of Lacepede. 



Very few specimens of this species have been preserved. Tiie skull 

 figured by Van Beneden and Gervais (Osleog. pi. 38, fig. 3) is presuma- 

 bly that received by Cuvier from Captain lloussaid,! though these au- 

 thors do not state that it is the same. I unfortunately failed to see this 

 specimen when in Paris. Gray (Cat. Seals and Whales, p. 277) gives 

 measurements of a skull in the same museum "from Peron," but I think 

 that there must be some mistake regarding this statement. There is a 

 skull (No. 3029) in the College of Surgeons, London, which Professor 

 Flower has identified with this species. Tiie four skulls (No^^. 17, 18, 

 19, 20) in the Leydcu Museum, which are labeled D. peronU, do not 



"* Recberches snr les Ossemens fossiles, 4""' dd., viii, pt. 2, 1830, p. 107. 

 t F. Cuvier has Roussart (Hist. nat. Cctaces, p. 1G5). 



