I. Prodrome of a Monograph of the Pinnipedes. 

 BY THEODORE GILL. 



(Communicated October 16, 1865.) 



The Seals of America have been hitherto little known, 

 and in the general works on the mammals of the northern 

 continent, they, like the bats and cetaceans, have been 

 omitted. 



With a view to the elucidation of the species, and at 

 the suggestion of Professor Baird, I have been induced to 

 undertake the examination of the collection of specimens 

 in skin, and the skulls and skeletons possessed by the 

 Smithsonian Institution and the Academy of Natural Sci- 

 ences of Philadelphia. To Mr. F. W. Putnam, Superin- 

 tendent of the Museum of the Essex Institute, and Professor 

 Wyman, I am much indebted for the kindness manifested in 

 transmitting to me the specimens they possessed, and the 

 opportunity thus afforded for comparison and study of 

 more extensive material. The results of the examination 

 of these specimens are now given, in so far as the classifi- 

 cation and relations of the primary groups and genera are 

 concerned, while I am obliged to defer until a more conven- 

 ient season the more elaborate exposition of the views I 

 have been compelled to embrace, as well as the discussion 

 of the limits and nomenclature of the species. 



Passing over the changes which the seal exhibits in its 

 progress to adolescence, I would advert to the peculiarities 

 in the geographical distribution of the several groups in 

 connection with their systematic relations. 



The three primary groups which may be elevated to 

 the rank of 1 families, in the first place, are very differently 

 distributed. 



