184 Dr. C. Liitken on some Odontoceti of 



without giving any reason for this determination. As both of 

 them have 53 vertebrae and 12 pairs of ribs, it would seem 

 from this alone that there is no real limit between this form 

 and 0. gladiator. Of course I did not stop at this, but I 

 have carefully examined and compared our five skeletons of 

 Orca gladiator [minor) of different sexes and ages, as well as 

 a certain number of crania, separate limbs, &c., without being 

 able anywhere to find anything to support the specific difter- 

 ences indicated by my predecessors. In this respect I must 

 range myself by the side of the northern zoologists who, by 

 the study of their own materials, have arrived at the same 

 results. As in Tursiops^ I find in all the characters indivi- 

 dual variations and variations arising from age, but nothing 

 more. I have particularly directed my attention to the crania, 

 to which one is in the habit of appealing in the first place, 

 and I have convinced myself that they present no differences 

 of any importance. But by this we have succeeded only to a 

 very small extent in advancing the question as to how many 

 species the genus Orca includes, and what these species are. 

 As regards the north I can only recognize two, and one of 

 these, that which bears the name 0. Esch'ichtii, needs to be 

 further studied upon new materials. 



III. 



Although the two northern species of the genus Lageno- 

 rhynchus are well known as regards their osteological charac- 

 ters, I have thought that it might be useful to submit to a new 

 comparison the very considerable materials at my disposal, 

 because these materials apparently form a more numerous 

 collection than exists elsewhere, and because, in general, one 

 has not often the opportunity of making such comparisons 

 between two very distinct species of the same genus of Odon- 

 toceti. It is therefore permissible to believe that the results 

 thus obtained may have a more general interest by aiding in 

 the solution of analogous questions in cases where the mate- 

 rials available are not so complete. The principal results 

 furnished by the comparison of four skeletons and of several 

 crania of each of the species in question are given in the 

 following statement : — 



L. alhirostris, Gr. L. aeutus, Gr. 



The lengtli of the skull in the The length of the skull is a little 



adult animal is to that of the whole more than two elevenths or one sixth 



skeleton as 2 : 11, and is equal to of the whole skeleton, and corre- 



the length of IG vertebrte. The sponds to 14 vertebrae. The muzzle 



