STEUCTUEE OF HOOKEE'S SEA-LION. 375 



that figure, that the nose agrees with 0. hooker i. The ears of 0. falklnndica are 

 evidently of considerable length compared to the length of the head ; so that, on the 

 whole, this species probably comes nearer to 0. hookevi, 0. pusilla, and their allies than 

 it does to O.jiibaia '. 



0. Jiookeri has been already figured by Dr. Gray in the illustrated account- of the 

 zoological material gathered during the voyage of the ' Erebus ' and ' Terror.' In that 

 figure a character is assigned to the species which I cannot believe to be correct from 

 what I have myself observed in 0. hookeri (see PL LXV. fig. 2). The nails on the digits 

 of the pes are drawn as being of nearly equal size, those of the first and fifth being only 

 a very little smaller. This is certainly not the case in the two individuals examined by 

 myself; in both these the three middle digits of the pes have long and well-developed 

 nails, while those of the first and fifth are only rudimentary. The drawing, however, 

 which illustrates Dr. Gray's ' Report ' was made from a stufi'ed specimen, and is, on 

 this account, less reliable. Even the skeleton of the foot shares in this peculiarity ; 

 the middle digits have the terminal phalanx ridged and pointed from the insertion of 

 a long claw ; the first and last digits have a flattened terminal phalanx. 



Dr. Burmeister ^ uses this character to distinguish 0. hookeri from 0. julata ; but I 

 am quite unable to confirm the accuracy of Dr. Gray's illustration of the hind limbs *. 

 T lay particular stress upon these points, because it might be imagined, from some 

 figures and descriptions which have appeared, that these points are of value in specific, 

 if not in generic, diagnosis. As the object of the present communication is mainly the 

 discrimination of the genera of Sea-Lions, I need not apologize for giving prominence 

 to the discussion of all such characters. 



Dr. Murie, in his valuable and exhaustive treatise ^ upon the external characters and 

 anatomy o^ O.juhata, has described and figured the manus and pes^ of that Sea-Lion. 

 The former limb has five extremely minute flattened nails corresponding to the five 

 digits ; the same is the case with 0. hookeri (see PI. LXV. fig. 1) and apparently 

 with other species. The pes of 0. julata presents exactly those characters which have 

 been already referred to in describing 0. hookeri ; and, moreover, the skeleton of the 

 limb presents a completely similar modification to that which occurs in 0. hookeri. 



In Mr. Clark's figure of the corresponding limb of 0. forsteri ^ the number and 



' Mr. (:kirk (P. Z. S. 1875, p. 664) remarks, with a figure (fig. 5), upon the peculiar nasal cartilages in his 

 0. forsteri; exactly the same disposition occurs, according to Burmeister's figure, in 0. fidMandwa. Unfor- 

 tunately I omitted to examine these structures in 0. hooheri. 



' Voyage of the ' Erebus ' and ' Terror.' Description of Mammalia, by Dr. J. E. Gray, pi. xiv. 



' Loc. cit. 



^ Mr. J. A. Allen (Bidl. Mus. Comp. Zool. Harvard, vol. ii. no. 1, p. 40), emphasizing these unlikely points of 

 difference, is inclined to unite again the two species ; I think that, apart altogether from the new facts which 

 I am able to bring forward in the present paper, this proceeding could not be justified. 



° Trans. Zool. Soc. vols. vii. and viii. 



« Loc. cit. vol. vii. pi. Ixvii. figs. 1,2. ' r- Z. S. 1875, pi. Uxi. 



3n2 



