THE NAUTILUS. 35 
and new species figured. Cionella lubrica and Pyramidula strigosa 
are among the northern species occurring in the Boundary region. 
The discussion of the Boundary fauna is followed by an extended 
treatment of the Lower Californian Bulimuli,in which a number of 
obscure matters are righted. In conclusion is given a list of marine 
mollusks from the termination of the international boundary and 
from San Clemente Island. 
Evidence is adduced indicating that within comparatively recent 
geologic time, probably Post-Pliocene, Mexico has been almost in- 
sulated from the Continent north of it. 
The Journal de Conchyliologie for April, 1896 (issued about 
April 7, 1897), contains an important article on Plewrobranchus and 
related genera, by Prof. A. Vayssiére, of Marseilles. 
Dr. R. Ellsworth Call has added a valuable paper to the scant 
literature of American cave faunas in his Notes on the Flora and 
Fauna of Mammoth Cave, Ky. (American Naturalist, May, 1897). 
The only mollusk found by him in the cave is a Carychium, consid- 
erably like C. exiguum, which he describes as C. stygium. About 
150 examples were collected in “ Mammoth Dome,” on the wet sur- 
faces of old bridge timbers, which have been lying undisturbed for 
forty or fifty years. 
Dr. Heinrich Simroth gives a preliminary communication upon 
Russian slugs,’ based upon the study of materials in the Zoological 
Museum of the Imperial Academy and the Senckenberg Museum 
at Frankfurt. The Caucasus Mountain region is the district of 
greatest peculiarity, having a number of special types. Simroth 
truly says that for the satisfactory working out of the species and 
their inter-relationships, the investigation of the genitalia and intes- 
tinal tract suffice; but for the understanding of the genera and 
their phylogeny, the other organs, especially the heart, pallial re- 
gion, kidney and lung must be examined, a condition very rarely 
fulfilled. The Testacellide and Arionide are briefly commented on, 
and the following genera of Limacide noted: Agriolimax, Para- 
limax, Lytopelta, Gigantolimax, Metalimax, Monochroma, Parma- 
cellu. Metalimax and Monochroma are new, the former near Para- 
limaz, but differing in the male genitalia; the latter is near Limaz, 
but the eye-retractor does not pass between branches of genitalia, 
1Annuaire du Mus. Zool. de l’ Acad. Imp. des Sci. de St. Petersburg, 1896. 
