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THE AMERICAN NATURALIST [Vol. LI 



lution as a land animal. This case seems to have some resem- 

 blance to that of a grapsoid crab at Bermuda, Sesarma ricordi 

 ^I.-Ed\v., of which a terrestrial variety has been described by 

 Verrill (1908, p. 328). It is my impression that the larger 

 marine specimens of G. agricola are less hardy, more easily 

 caused to fragment by handling, than are those taken on land. 

 This may, however, be merely a physiological consequence of 

 differences in habitat, which could be exhibited within the life- 

 history of a single individual. I have not been able to keep the 

 salt water specimens alive after abruptly transferring them to 

 damp earth. The young individuals, however, are quite hardy, 

 and seem capable of enduring this treatment for several days at 



These observations add further, and possibly final, weight to 

 the argument that some, at least, of the land nemerteans have 

 proceeded directly from ancestors inhabiting salt water. 



W, J. Crozier 



Agar's Island, Bermuda 



REFERENCES 



Coe, W. R. 



1904. The Anatomy and Development of the Terrestrial Nemertean 



(Geonemertes agricola) of Bermuda. Proc. Bost. Soc. Nat. 



Hist., Vol. 31, pp. 531-570, pi. 23-25. (Contrib. Bermuda 



Biol. Sta., No. 4.) 

 Montgomery, T. H., Jr. 



1895. The Derivation of the Freshwater and Land Nemerteans, and 



Allied Questions. Jaur. MorpJi., Vol. 11, pp. 479-484. 



1902. The Bermuda Islands. (Repr. from Trans. Conn. Acad. Sci., 

 Vol. 11, with changes.) New Haven, x -f 548 pp., 38 pi., index. 

 1908. Decapod Crustacea of Bermuda. I. Brachyura and Anomura. 



