THE NAUTILUS. 137 
RECENT PUBLICATIONS. 
Appenprx TO MARINE SHELLS OF SouTH AFRICA, by G. B. 
Sowerby (30 pp.,3 pl.). The total number of species is brought up 
to 1051 in this appendix. Among numerous new forms may be 
mentioned Fulgur africanum, a form resembling young F. carica ; 
two fine Ancillas, a Basterotia and several new forms of Scintilla as 
as of special interest. The rare Voluta festiva Lam. is also recorded. 
ARMATURE OF HELICcoID Lanp Sets. 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 ectitting 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 MuraTions 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.’ ” 
Tittorina littorea is selected for study. First collected at Bathurst 
on the Gulf of St. Lawrence in 1856, 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 : 
“T and II, more variable in its stature. III, 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.” 
