THE NAUTILUS. 137 



RECENT PUBLICATIONS. 



APPENDIX TO MARINE SHELLS OF SOUTH AFRICA, by G. B. 

 Sowerby (30 pp., 3 pi.). The total number of species is brought up 

 to 1051 in this appendix. Among numerous new forms may be 

 mentioned Fulgur africamnn, a form resembling young F. carica; 

 two fine Ancillas, a Basterotia and several new forms of Scintilla as 

 as of special iuterest. The rare Valuta j 'estiva Lam. is also recorded. 



ARMATURE OF HELICOID LAND SHELLS. Mr. G. K. Gude still 

 continues his series of articles under this head in Science- Gossip. 

 The extensive genus Plectopylis still furnishes species for description 

 and illustration. In this group, as in many other genera of land 

 snails, the most important characters for distinguishing species, and 

 for their grouping, are to be seen only by cutting the shell to expose 

 the peculiar system of internal barriers and teeth. In some species 

 of Plectopylis these are wonderfully complex, forming truly a 

 ' crooked gateway." It must be said that in these papers Mr. Gude 

 supplies a large amount of information not elsewhere to be found. 



THE VARIATIONS AND MUTATIONS OF THE INTRODUCED LIT- 

 TORINA, by Hermon C. Bumpus (Zool. Bulletin I, No. 5, p. 247, 

 February, 1898). "The observations recorded in this communica- 

 tion were made for the purpose of ascertaining additional facts rela- 

 tive to the variability of ' introduced species.' ' 



Littorina littorea is selected for study. First collected at Bathurst 

 on the Gulf of St. Lawrence in 1855, the southward migration of the 

 species is traced to New Haven (1880). 10,000 shells were collected 

 from ten American, and 3,000 from three English localities for 

 measurement and weighing, the results being summarized as follows : 

 " We may then conclude that the periwinkle, subjected to a new 

 environment, and presumably emancipated from many of the re- 

 straining influences of natural selection, has become in any and all 

 American localities : 



" I and II, more variable in its stature. Ill, more variable in its 

 course of growth. IV, more variable in weight. V, more variable 

 in bulk. VI, more variable in limitations and boundaries of the 

 color patterns. 



" While presenting these extremes of variation, the American type 

 of Littorina littorea, when compared with the European type, is more 

 elongated, lighter in weight, more bulky, and the color markings 

 are less pronounced." 



