REVIEWS. 3 



would have had some value as showing the variation in respect to 

 this ratio that obtains between specimens of the same species. 

 But the idea of determining the relative slenderness of two ani- 

 mals by the number of times the length of the head is contained 

 in the total length of the body, is, to say the least, a novel one to 

 me, since slenderness and robustness of form usually involve, as 

 is well known, the head as well as the trunk, as a little reflection 

 will doubtless at once convince my reviewer. That the expression 

 "'form more slender' of the former [OufopAocmce] implies a 

 greater relative total length for these animals than the head alone 

 would indicate," is an announcement for which I was quite unpre- 

 pared. 



In regard to the length of the ear in the two groups, it appears 

 that Dr. Gill has also been unfortunate in his generalizations. Ac- 

 cording to his quoted measurements, the ear in the longest-eared 

 species of the hair seals (Eumetoj)fas) scarcely equals that of the 

 shortest-eared species of the fur seals, but he seems to have for- 

 gotten that the bulk of Eumetopias is several times that of the 

 largest of the fur seals, so that while the ear is absolutely but 

 little longer in the fur seals than in the longest-eared hair seals, it 

 is relatively very much longer. 



Having said this much in regard to the validity of the charac- 

 ters I gave as distinctive of these two groups, I desire to add a 

 word in respect to the matter of " conservatism." Dr. Gill says, 

 "In the case of doubtful species at least of those which have 

 tangible characters, but the value of which may be dubious some 

 naturalists refer such at once to species which they appear in their 

 judgment to most resemble, while others probably most retain 

 them with reserve, awaiting future information. Of the former 

 school, Mr. Allen is an ardent disciple, and finding a certain 

 range of variation in some know^n form, he concludes that analo- 

 gous variations are only of like value." In reply to this, I will 

 only say that my practice is to never reduce to a synonyme any 

 species presenting " tangible characters," or even those which ap- 

 pear to have such characters, or where the probability seems to be 

 that it may be distinct, though not as yet properly characterized. 

 When no evidence of the validity of a given species has been 

 advanced, which in the light of present facts can be so considered, 

 I deem it subservient to the interests of science to refer them to 

 the species to which they seem evidently to belong; as in no 



