34 THE NAUTILUS. 



Heterodonax bimaculata is not only collected at San Pedro all the 

 year round, but is reported as far north as Anacapa Id. one of the 

 Channel Islands off Ventura Co., California. Fossil species of 

 Psammobiidje of the Eocene, Miocene and Pliocene formations are 

 listed. A long list of shells that have been incorrectly named are 

 appended under the title " Synonyms and Corrections." Some idea 

 of the confusion which must have existed among some of the fossils 

 of this family may be inferred when we find no less than five names 

 have erroneously been bestowed upon Heterodonax bimaculata Liu. 

 Dr. Dall's revision will be especially valuable to conchologists on 

 the S. Atlantic and Pacific Coasts. I/. B. W. 



ON THE MODIFICATIONS OF THE APEX IN GASTROPOD MOL- 

 LUSKS, by Frank C. Baker, (Ann. N. Y. Acad. Sci., IX, 1897). 

 The apices of numerous species, including representatives of the 

 main families of Gastropoda are described and illustrated by three 

 plates of outline figures, drawn by the author. No considerable 

 departures from a simple form occurred except in the Rhachiglossa. 



THE POST-PLIOCENE NON-MARINE MOLLUSCA OF ESSEX, by A. 

 S. Kennard and B. B. Woodward, (Essex Naturalist, X, 1897, pp. 

 87-109). This extensive paper apparently covers the subject in a 

 thorough manner. Individual variation in the Pleistocene was even 



O 



more marked than at the present day. The absence of Helix 

 pomatia furnishes additional proof of the theory that it is post- 

 Roman in its introduction into England ; but H. aspersa has been 

 recognized from pre-Romau deposits. Eulota fruticum (now extinct 

 in England) occurs ; and Oyclostoma elegans was more widely dif- 

 fused than at present. Some of the fossil species are more boreal in 

 the modern fauna ; however there are also some species more south- 

 ern in present distribution, so that a colder climate is not necessarily 

 to be predicated. Helicella caperata is the only species which has 

 increased in size since the Pleistocene, all the other forms having 

 certainly diminished. " There can be no doubt that the Pleistocene 

 molluscau fauna was in every way a finer one than that now exjst- 

 iug," a conclusion of considerable interest, agreeing as it does with 

 the mammalian fauna, which however has, of course, been affected 

 by human intervention. The comparative age of the several expos- 

 ures is fully discussed. 



Another paper, " THE MOLLUSCA OF THE ENGLISH CAVE DEPOS- 

 ITS " by the same authors, appears in Journ. Malac. Soc. Lond., 



