316 ANNUAL OF SCIENTIFIC DISCOVERY. 



scribod in their localization. Their powers of locomotion, instead of 

 facililatiii<^ tlieir distribution over a wide surface, only seemed to 

 allow tlicm to remain in a o^iMiial clime. With reference to the 

 mammalia, the localization of the dilVcreut species was still more 

 strikin<j. He described several families of aijuatic mammalia 

 found in Brazil, both cetaceous and ixichj'dermatous — the tapir 

 anil the peccary beini^ the only genera of the latter. The exist- 

 ence of the fossil remains of mammalia, l)otli in Iha/il and in the 

 United States, was next spokini of at some Icni^th, and tlu^ impor- 

 tance of the study of these remains, in determining the origin and 

 distribution of animals, was alludeil to. There were evidences, 

 the lecturer said, that th(! rhinoc(;ros, the (dephant, and the 

 megatherium, once had i-epresentatives in this country; and a 

 Duteii naturalist had discovered a larger number of extinct species 

 of animals in Brazil than now exist there of living species. 



He next passed to the families of rodents, ruminants, and car- 

 nivorous animals, in all of which was manifested the same dissim- 

 ilarity to the families existing at the north, and a similar peculiar 

 circumscription of types. In the tropical regions, the only i-odents 

 Avhieh approach ours in aj^pearance are th(i sriuirrels, and these 

 are few in uuml)er. In the lamily of ruminants there are no bulls, 

 cows, sheep, or antelopes. Even the deer, so numerous in North 

 America, Europe, and Asia, are in Brazil reduced to a few small 

 species, not exceeding the size of the common goat. The whole 

 host of fur animals, characterizing northern regions, are wanting, 

 and they are replaced by mau}^ varieties of skunks. 



CLASSIFICATION OF MOLLUSCA. 



In the proceedings of theEssex Institute, Salem, Mass., vol. iv., 

 p. 1()2, is an article by Edward S. Morse on " A Classification of 

 Mollusca, based on the Principle of Cephalization." He adopts 

 the name " Saccata," proposed by Mr. Hyatt, as more fully ex- 

 pressing the type of the division than the term " Mollusca; " this 

 name not only expressing the plan, but being equivalent to the 

 titles Vertebrata, Artieulata, and Iladiata, and being in no way a 

 qualitative api)ellation. The gradual morjjhological changes of 

 the contents of the sac, and all other relations, are based on the 

 principle of cephalization. " According to this principle, cephalic 

 power is manifested either as a mechanical, sensorial, or jisychical 

 force. Thus the Cephalopods possess, in the greatest measure, 

 all three; while Gasteropods, not indicating, to any great extent, 

 aggressive action, may be said to manifest but little psychical 

 power; and the Lamellibranchiates manifest essentially only 

 mechanical action. We have cephalic power manifested in the 

 mechanical action of the foot, thus : — 



"1. Lamellibranchs — locomotion. 



"2. Gasteropods — locomotion, prehension, 



*' 3. Cephalopods — locomotion, jirehension, and aggression. 



" The characters may thus be stated : — 



" Saccata. — 1. Animals of varied forms, without a radiate struc- 

 ture and without articulations. 



