118 BULLETIN ;5li, UNITP^D STATES NATIONAL MUSEUM. 



PHOC^NA COMMUNIS Lessou. 



Delpliinus phocama, Linii6, Syst. Nat., lOtli ed., 1758, p. 77. 



Phoca'tia comm}inis, Lesson, Man. de Mammalo^ie, l>i'27, p. 113. {Fide Flower.) 



rhoccrna braclii/cittm, Cope, Proc. Acad. Nat. Sci. Phila., IrfO.'), p. '279. 



Fliocaua vomerina, Gill, Proc. Acad. Nat. Sci. Pliila., ISGl, p. H.'-'. 



? rhocwna lineala, Cope, Proc. Acad. Nat. Sci. PLila., 187G, p. 13.'). 



Of Pliocteuas from the east coast of America there are iu the national 

 collection three complete skeletons, two of young individuals and one 

 of an adult; four additional skulls ; and three casts i'rom fresh speci- 

 mens. Ol P. vomerina there is one young skeleton and three skulls. 

 There are also in this collection the type-cast of i'. lineata and a skele- 

 ton and. two skulls of P. communis. 



All the specimens from the east coast, except No. IGGIO, Caj)e May, 

 N. J., adult 9 , are from Eastport, Me., and are not adult. The number 

 of vertebrae in the three skeletons is as follows: 



(o) No. 13301, Eastport, Me., C. 7; D. 13 ; La. & Ca. 11 = G4. 



[b) No. 13305, Eastport, Me., C. 7 ; D. 12; L. & Ca. 2U -f *=?. 



(c) Unnumbered, Eastport, Me., C. 7 ; D. 13; L. & C:i. 4i5r=(i(i. 

 {(l) No. 16G10, $ , Cape May, N. J., C. 7 ; 1). 13 ; L. & Ca. 47=()7. 

 In the skeleton of P. vomerina the formula is as follows : 



(e) No. 14331, California, C. 7; D. 12; L. & Ca. 45 (+l)t = Gr) (<.r (if;). 



Three skeletons from the European coast, mentioned !)y Fischer, li;i\ c 

 the vertebra' as follows : 



(/) C. 7; D. 13-14; L. & Ca. 4.5-48=G5-G9. 



It is evident that no character can be derived from dilrerences in tliii 

 number of vertebra'. 



In all the American skeletons the caudal artery fiist perforates the 

 thirty-ninth vertebra counting from the last vertebra. This is, however, 

 a character of no value in dilferentiatiugP. co?»?jrM></.S', since in the skele- 

 ton (igured by Van Benedeu and Gervais (Osteog., PI. lv) the first per- 

 foration is in the thirty-eighth vertebra. 



In his paper in the Proceedings of the Philadelphia Academy, 187G, 

 Professor Cope brings forward the shape of the portion of the vomer 

 visible behind the palatines as a specitic character. Iji two of the four 

 skulls from Eastport the vomer appears behind the posterior margin 

 of the palatines, while in the remaining two it does not. The same is 

 the case as regards the four skulls from the Pacific coast: iu two it 

 appears, in the others, not. In one of the skulls of P. communis figured 

 by Van Benedeu and Gervais, the vomer is visible, iu another it is not. 

 It is certain, therefore, that this character, as already' stated, is value- 

 less. 



As regards the other characters given by Professor Cope for his P. 

 brachycium, — the shape of the muzzle, the prenarial triangular area, 



* Most of the caudal vertebra; are lacking. ^ 



t The last rudimentary vertebra is evidently lacking. 



