98 THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



difference from No. 21492, from Cape Cod, in the National Museum, while No. 

 16252, also from Cape Cod, has D. 14, L. 11, a difference of one lumbar. Some 

 European specimens of M. lonr/lmana have 10 lumbars and others 11, while the 

 number of dorsals remains constantly at 14. 



Cope com})ares his M. hellicosa in many particulars with M. longimana, and 

 also occasionally mentions M. osphyia. The differences which he finds between M. 

 hellicosa and M. longimana are as follows : 



(1) The whole form of the nasals is different in hellicosa and "at once dis- 

 tinguish it " from longimana. 



(2) The ramus of the mandible is more slender in hellicosa. 



(3) The elevated coroiioid of hellicosa at once distinguislies it from longimana. 



(4) The head bears a greater proportion to the length of the body in hellicosa 

 than in longimana. 



(5) The orbital plates of the frontal are less concave anteriorly in hellicosa. 



(6) Tiie first rib is broadei' (if Rudolphi's' figures of longimana are correct). 



(7) The pectoral fin is black externally in hellicosa, but " entirely white in 

 Arctic Megapterar 



We will take up these differences in the order in which they appear above, 

 considering them, however, as far as possible, in connection with specimens fi'om 

 the American side of the North Atlantic. As to whether these latter are identical 

 with M. longimana has to be considered later. 



The nasals of M. hellicosa, as described and figured by Cope, though they may 

 differ fi'om those of European specimens of longimana, are very similar to those of 

 skeleton No. 21492 fi'om Cape Cod, Mass. The chief difference is that in the latter 

 specimen they are only very imperfectly serrated proximally for articulation with 

 the frontal. The nasals of hellicosa seem long as compared with those of No. 

 21492, which is probably a skeleton of about equal size. They are 9 inches long in 

 the foi'mer, 7|- inches in the lattei'. 



The importance of the slenderness of the ramus of the mandible in hellicosa I 

 cannot estimate, as I have not seen that part of the skull. Cope's figures of the 

 coronoid process indicate that that process is not larger than, or in any wise 

 especially different from, the same part in the Cape Cod specimens. 



The next point of difference mentioned b}' Cope is that in hellicosa the head is 

 longer in proportion to the body than in longimana. He gives the length of the 

 cranium in the former as 9 feet and the total estimated length of the skeleton, 31 

 feet 4 inches. This makes the skull 28.7 % of the total length. As the skull with 

 the premaxillaries is undoubtedly some 6 inches longer, however, its proportion 

 to the body would appear to be still greater. Skeleton No. 21492 from Cape Cod, 

 Mass., is 33 ft. 10 in. long, and as it lacks probably the two final caudal vertebrae, 

 about 7^ inches should be added, making a total of 34 ft. 5^ in. As the skull is 

 but 9 ft. 5 in., its proportion to the body is but 27.3 %. It is to be observed, how- 

 ever, that in the type of hellicosa the scapula, axis, and humerus indicate an indi- 

 vidual at least as large as No. 21492, and hence it is open to question whether 



