10 THE NAUTILUS. 



nates. The " penis sac " of Mr. Baker's descriptions is the penis, 

 while the non-invertihle tube surmounting it, which he designates 

 " penis," seems strictly homologous with the epiphallus of land snails. 

 Since these distinctions were introduced by the writer in 1892, they 

 have been adopted universally by workers on land snail anatomy, 

 and in the interests of uniformity it seems well to use the same terms 

 in aquatic pulmonates. 



In his attitude toward species Mr. Baker sides with the " splitters," 

 quite as frankly as Binney, in Land and Fresh-water Shell II, in- 

 clined towards the " lumpers." It may turn out that the author has 

 attached too much importance to local forms, and failed to make due 

 allowance for variation of the same specific type under varying spe- 

 cial conditions. Yet after all, the question is not one for a snap 

 judgment ; the status of each form must be decided separately, and 

 often by local study, where the influence of local conditions on the 

 associated species can be taken into account. It usually turns out 

 that a work of this nature raises more questions than can be settled 

 by a generation of conchologists. One of its valuable features is in 

 stimulating investigation of the vast variety of forms shown to exist, 

 of the correlation of shell-characters with ecologic factors, etcetera. 



Many new species and subspecies, most of them originally described 

 in this journal, are illustrated here for the first time by excellent 

 photographic figures, which occupy 34 of the 58 plates, the others 

 being devoted to anatomical and ecologic illustrations. The facts of 

 distribution are graphically summarized by many maps printed in 

 the text. H. A. P. 



Descriptions of nevt mollusks of the family Vitrinel- 

 LiD^ from the west coast of America, by Paul Bartsch. (Proc. U. S. 

 Nat. Mus., vol. 39, pp. 229-234. 1911.) Gyclostroma baldridgei 

 (Gulf of Cal.); G. miranda (San Pedro); G. «c(fam« (Panama); Gir- 

 culus liriope (Gulf of Cal.); G. diomedeae (Panama); Gyclostromella 

 dalli (Gulf of Cal.), are the new species described. 



The recent and fossil mollusks of the genus Alabina 

 from the west coast of America, by Paul Bartsch. (Proc. U. S. N. 

 M., vol. 39, pp. 409-418. 1911.) Seven new species and two sub- 

 species of this genus of minute Bittium-like shells are described from 

 the recent and Tertiary faunas, and all of the known species are re- 

 viewed. Like the last paper, this is illustrated with excellent line 

 engravings. 



