NOTES OX SOME SKELETONS AND SKULLS OF POKPOISES 

 OF THE GENUS PEODELPIIINUS, COLLECTED BY DK. W. 

 L. ABBOTT IN THE INDIAN OCEAN. 



By Fredekick W. True, 



Curator of ihe Department of Mammnh. 



During bis recent cruise iunoug the islands north of Madaj?ascar, 

 Dr. Abbott collected three complete skeletons and two skulls of 

 porpoises. These, Avith notes and measurements, he has very kindly 

 presented to the National Museum. The notes include a description of 

 the coloration of each specimen captured, and thus it is possible to 

 correlate the extermil characters with those of the skeleton. This is a 

 most important matter, and especially so m this instance, as the speci- 

 mens all belong to the genus Proilelphinufi, than which there is no more 

 dilhcult group among the Delphinida'. 



It is witli considerable diffidence that I attemi)t to identify Dr. Ab- 

 bott's specimens with any of the described species of ProdelpMnus. 

 The practice of establishing si)ecies on single skulls was formerly fol- 

 lowed in connection with this genus as elsewhere in the Delphinidiv. 

 But it has been pointed out, especially by Sir William Flower, that in a 

 series of skulls of ProdeJ phi n us, while those at the extremes may show 

 differences which would entitle them to be regarded as specifically 

 distinct, these differences blend together in the middle of the series. 

 Hence, in considering the identity of any iiarticular skull, it is often 

 doubtful to which one of several nominal species it should be referred. 



Much new light has been thrown on the relationships of the species 

 of ProdeJphinushY Dr. Liitkenin his most valuable work upon this and 

 other genera of Delphinidic,* published in 1889. Having in his posses- 

 sion an excellent collection of skeletons of various species of Prodel- 

 pliinus, accorai3anied by color-notes, measurements, etc., he Avasableto 

 furnish much fuller information than any previous writer. For several 

 species he has given the number of vertebra-, the position in the ver- 



* Bidrag til Kuudskab om do tro pelagiske Taudhval-Slaegter Sietio, Delphinus og 

 J'rodelphiuns. Videiisk. Selsk. Skr., 6. Eaekke, naturvid. og math. Afd., V, 1, 1889. 

 At tlie time a copy of this paper reached me, my own work ou the Delpliinidie (A 

 Review of the Family Delphiind;e. Bulletin of tlie U. S. National Museum, No. 36, 

 1889) was passing through the press, and I was unalde, therefore, to make as good use 

 of it as I should have desired to do. 



Pro<fLHlinus X;itiiiii;il Museum, Vol. XVII— Xo. 982. 



33 

 Proc. N. M. 94 -3 



