NORTHERN SPECIES OF ORCA. 183 



a perfectly full-growii, even an old individual, for the ossification of the vertebræ was not only quite 

 complete, but the teeth, of which there were thirteen on either side of the upper jaw, and eleven in 

 the lower jaw, were quite closed at the points of the roots, except four which were quite hollow, 

 and all the crowns of the teeth were worn down to the very gums. We believe, therefore, we 

 may set up this specimen as a type of the female of the smaller species, just as the two Bergen 

 specimens have already been set up as types of the male. But then we come to two rather 

 important results, relative to the sexual differences in this species : 1, that the female of this 

 species, as of the Cetaceans in general, is somewhat (one or two feet) larger than the male ; 

 2, that the dorsal fin is somewhat smaller. In one of the specimens, of which the skeletons are 

 preserved in the Museum at Bergen, and whose fins bore a very close resemblance to those ot 

 Schlegel's specimen, the length of the dorsal fin along its anterior edge was 2' 3" Norwegian 

 (Danish) measure, according to the statements of Professor Lilljeborg, by which measurement, how- 

 ever, it seems difficult to find out the real height of the fin. But the dorsal fin of the Greenland 

 skeleton, which is one foot longer than the longest of those from Bergen, is only 1' 8|" long ; 

 and Dr. Koren has had the kindness to send me a paper pattern of the dorsal fin of one of these 

 Bergen killers, adding expressly that it was of about the same size in both of them, and this 

 pattern is really only 1' 10 J" high. The pectoral fin which in the Bergen males, according to 

 Dr. Koren's statement, were 2' 9|" long, were 1' 11" long and V f" broad, in the Greenland 

 specimen ; the breadth of the caudal fin was 3' 3". Thus, the superior power in the fins of the 

 males seems at any rate to prevail, though to a far inferior degree than we had reason to presume, 

 before the separation of the two species. 



The distribution of colours in the Greenland specimen, as far as it can be seen from the 

 figure drawn by Mr. Bloch, did not difier from the common colours of the northern killers. 



The other two Orca skeletons, already for some time belonging to the museum, are much 

 smaller; the one (Mr. Thomsen's) 11' 11" long, the other (the one from the Faroe Islands) 

 11' 9". At first it seemed to be very hkelj', that both these belonged also to the small species. 

 But a more minute consideration of them has led to an opposite result. 



To begin with Mr. Thomsen's from the eastern coast of Jutland, it is indeed only 

 1 1' 1 1" long, but at the same time it is so young, that by the experience I have obtained in judging 

 about skeletons of Cetaceans at difierent periods of age, I cannot suppose it to have advanced 

 much beyond the sucking age, nor, indeed, to have attained to half its full length. All the 

 teeth (it had thirteen teeth in either side of both jaws, and besides one intermaxillary tooth in the 

 upper, and a corresponding small foremost tooth in the lower jaw) are occupied by the cavity of 

 the dental pulp to that degree that they are thin as paper up to the very point of the crown ; 

 in the carpus there is only one slight trace of ossification ; all the extremities of the long bones 

 are perfectly cartilaginous (see the woodcut, p. 173, which was taken from this specimen), the 

 three foremost osseous portions of the sternum are separated by rather broad cartilaginous in- 

 terspaces, and the fourth is entirely cartilaginous ; all the vertebral processes are only about 

 half ossified, and the ossified portions are still very brittle. 



Now, it is a matter of course, that when size is to be employed as a character of species, it is 

 only in full-grown individuals, as the two Bergen skeletons, and those of NUsson, Benzon, and 

 Bloch, that it can be used without making allowances, and that in all other cases we must try 

 to conjecture from the more or less advanced state of development of the individual how much 

 larger it would have grown if it had lived. By following this principle, I suppose that the 



