954 American Work on Recent Mollusca in 1881. [December, 



with the rest. Ke also places some facts on record in regard to 

 an asserted desiccation of the island of Santa Cruz, and concludes 

 that there is no sufficient proof of it nor of an alleged conflagra- 

 tion caused by the French colonists in 1650. 



To the " History of Fremont county, Iowa," Professor Call 

 has contributed a chapter on the geology and natural history, 

 which has been separately issued, with new pagination, with the 

 date of Nov., 1880. The Mollusca are treated of on pp. 34~3 6 » 

 where is given a list of thirty fresh-water and ten land shells, 

 none of them peculiar to the locality, more than half of which 

 are bivalves, mostly Naiades. 



In the Annals N. Y. Acad. Sci., n, 18S1, pp. 129-139. Dr. 

 Stearns discusses the introduction of Helix aspersa L., in Califor- 

 nia, together with the synonymy, relations and habitat of several 

 South Californian species. 



" On the geographical distribution of certain fresh-water mol- 

 lusks of North America, and the probable causes of their varia- 

 tion " (Part 1, Jan., 188 1, pp. 8; Part 11, July, 1S81, pp. 1 1 ; Journ. 

 Cincinnati Soc. Nat. Hist, iv, 1881). The two papers above cited 

 contain an interesting resume, from Professor Wetherby's point 

 of view, of a number of singularities in geographical distribution 

 of American fresh-water shells. " We are of the opinion that 

 when the facts are fully determined in regard to the fossil as well 

 as the recent forms, which unfortunately is not yet the case, 

 results of value will be obtained. The author wisely does not, as 

 yet, endeavor to formulate any results, but calls attention to the 

 facts with a promise of further studies in the future. 



Stearns (Am. Nat., May 1881, pp. 362-6) discusses the distti- 

 bution and synonymy of " Mya arenaria in San Francisco, bay, 

 arriving at the doubtless correct conclusion that it has been intro- 

 duced probably not earlier than 1872 or 1873, on oyster "seed," 

 planted by importers from the eastern coast, to grow and fatten 

 in the bay. It has now almost entirely superseded other "clams ' 

 in the San Francisco markets, and has spread or been introduced 

 also at Santa Cruz. 



Dr. Lockwood notes (Am. Nat., Nov., 1881, p. 908) the find " 

 ing of the third fresh specimen (since 1876) of Argonauta argo 

 L., on the New Jersey coast. Two occurred at Long Branch^the 

 other fifteen miles south of it. One was living when found. The 

 argonaut may therefore be said with truth to belong to the fauna 

 of the east coast of the United States. 



