1882.] American Work on Recent Mollusca in 1881.. 883 



"Observations on Planorbis" (Proc. Acad. Nat.Sci. Phil, 1881, 

 pp. 92-1 10), by Dr. R. E. C. Stearns, discusses several interesting 

 questions, such as " Are the shells of Planorbis dextral or sinis- 

 tral ? " He finds most of the species examined sinistral, others 

 dextral and occasionally the same species may be coiled either 

 way. Certain aspects of variation in American Planorbes are 

 considered and pregnant suggestions made. The paper is well 

 illustrated. 



An abstract of a paper by Professor E. S. Morse, on changes in 

 the proportions of Mya and Lunatia since the Indian shell- 

 mound period (if such an expression may be permitted when the 

 mounds were probably added to continuously up to the historic 

 period), appears on p. 323, Am. Journ. Sci., XXII, Oct., 188 1, and 

 an erratum to the same on p. 415. Professor Morse, as in Jap- 

 anese shell-heaps, believes he has found good evidence of a 

 change in the proportions of these shells in the differences be- 

 tween the average measurements of a large number of specimens 

 from the shell-heaps on the one hand, and from the present shore 

 on the other. While there seems no reason why such a change 

 may not have taken place, it is still evident that the satisfactory 

 demonstration of the proposition is beset with no little difficulty. 

 The original paper was read before the Cincinnati meeting of the 

 American Association for the Advancement of Science, in Au- 

 gust, 1 88 1. 



S. P. Robins has an article on " Natural selection and the ink 

 bag of dibranchiate Cephalopods," in the Canadian Naturalist 

 (ix, No. 9, pp. 414-420, Dec. 29, 1880), containing some specula- 

 tions on this subject. 



Minot has, in the Journal of Otology for i88r, an article in 

 which the available information on the otoliths of mollusks is 

 brought together, but the recorder has not seen a copy of it. 



Abyssal mollusks, faunal and descriptive papers. — The mol- 

 lusks of the deep sea have recently attracted considerable atten- 

 tion. Owing to their peculiar relations to the faunae of other 

 shores, the deep-sea animals have some right to be considered 

 under a separate head. Those of the Gulf of Mexico and the 

 Caribbean sea, dredged by the Blake, form the subject of a " Pre- 

 liminary report on the Mollusca," by W. H. Dall (Bull. Mus. 

 Comp. Z06L, ix, No. 2, pp. 33-144, July to December, 1881). To 

 secure priority, advance sheets of each signature were sent to all 



