1895. RESULTS OF '^CHALLENGER" EXPEDITION. 73 



Trichecus (walrus) into an Atlantic species differing from that 

 frequenting the North Pacific Ocean, as has been proposed by 

 Mr. J. A. Allen. 



Another chapter describes the brain of the walrus and of the 

 elephant seal, and compares the arrangement of the convolutions 

 and fissures of the cerebrum with those present in the brains of 

 carnivora, apes, and man. It concludes by giving, in a tabular form, 

 the fissures and convolutions in the brain of a dog, which apparently 

 have homologous arrangements in the ape's brain. 



The memoir on the seals concludes with an appendix, con- 

 taining a detailed description by Dr. W. C. Strettell Miller, of the 

 myology of several species of seals from the author's collection. So 

 far as the specimens permitted, the nerves which supply the muscles 



were dissected and described. 



William Turner. 



The collecting of Land Mammals had, as a matter of course, 

 httle place in the official programme of the voyage of the " Challenger " ; 

 but, nevertheless, when any specimens were by accident obtained, 

 they were preserved, and, by the end of the cruise, amounted to about 

 sixty in number. 



Some few of these, such as a Thylacine, Armadillo, Platypus, 

 were handed over to Professor D. J. Cunningham for dissection, and 

 resulted in his valuable paper on " Some Points in the Anatomy of 

 the Thylacine, Cuscus. and Phascogale," in vol. v., while the majority 

 were sent direct to the British Museum, where they now are. 



The value of these specimens lies not in their novelty or rarity 

 (for being mostly obtained near seaport towns, and more or less by 

 accident, without systematic trapping, they are almost wholly well- 

 known species), but in the accurate particulars as to their localities and 

 dates which accompany them. Thanks to these particulars, bats from 

 Hawaii, shrews from Manilla, moles from Japan, and mice from Chili, 

 all have their value to the specialist working at the several groups, 

 even if not of sufficient importance to demand a general account of 

 the collection. 



It is hoped that another time, whether on a great expedition hke 

 that of the " Challenger," or during ordinary surveying voyages, a few 

 . traps, large and small, may be set out systematically whenever and 

 wherever possible, for the results are sure to be of value sooner or later. 

 P'ew but specialists are aware how incredibly ignorant we are of the 

 exact distribution of mammals, not so much of the great groups, but 

 of the species, while much of this knowledge will by degrees become 

 more and more impossible to obtain, owing to the rapid spread over 

 the earth's surface of Europeans, pigs, dogs, rabbits, rats, etc. 



The visit of such a ship as the " Challenger " to all sorts of out- 

 of-the-way islands, would, therefore, be an opportunity for gaining 

 information about distribution, habits, etc., which could never be 

 obtained by the ordinary mammal collector, who has to ignore known 



