6 REVIEWS. 



the eared seals, have the "sagittal groove," etc., as above de- 

 scribed, as do also the males till they have attained nearly their 

 full size. The sagittal crest in the males of Eumetopias and 

 Callorhinus rises at first as a double ridge on each side of the 

 sagittal suture, beginning at the hinder part of the skull. It 

 develops most rapidly in its posterior part, and gradually ex- 

 tends anteriorly to a point opposite the orbital processes. Grad- 

 ually the laminae of this double plate become soldered into one, 

 uniting first posteriorly, while anteriorly the crest remains com- 

 posed of two closely applied thin plates, which, in old age, be- 

 come firmly united the whole length. The sagittal crest in old 

 male skulls of Zalophus hence differs from the corresponding crest 

 in Eumetopias and Callorhinus, only in being relatively somewhat 

 higher, and in being more produced anteriorly. I am not sure, 

 however, that in very aged animals even this slight difference 

 would be constant. In one of the skulls of Zalophus I have seen, 

 the two plates were not entirely soldered at their anterior end, 

 thus indicating their development primarily as a double plate, as 

 in Eumetopias and Callorhinus. The only other character given 

 as separating these two groups that of the rostral profile I 

 deem too trivial to require more than the incidental remark already 

 given to it. 



In concluding, I may add that the deservedly high standing of 

 my critic _as a naturalist seemed to demand from me, in justice to 

 myself, some notice of his sweeping criticisms, especially since 

 not merely the assumed value of the characters given by me as 

 distinguishing what I considered to be two primary groups of the 

 Otariadce were questioned, but also even the existence of such 

 distinctions ; but more especially it was due to the interests of sci- 

 ence that his incorrect diagnosis of one of the two groups he con- 

 siders as the two primary groups of this family, should not pass 

 unnoticed, since on this error was based a new classification of the 

 Otariadce. Having done this, the writer will here let the subject 

 rest, J. A. A. 



