No. 384.] REVIEWS OF RECENT LITERATURE. 957 
the very large immigration of forms from the Mississippi and Ohio 
valleys is found by the author in the topographical changes inci- 
dent to the glacial period. The formation of the Des Plaines and 
Maumee outlets to the lake region, as the ice-sheet receded, established 
the channels along which the Unionidae of the Mississippi and the 
Ohio entered the Michigan area. The opening of the Grand-Saginaw 
valley as an outlet for the glacial lake Maumee into Lake Michigan, 
and the subsequent closing of the Maumee outlet, afforded the 
opportunity for the Unionide of the Mississippi to invade this 
region. It is a significant fact that the present range of the most of 
the invading species is still confined within the beach lines of the 
glacial lakes. CAK 
The Plankton of Puget Sound.!— As the result of the examina- 
tion of a vertical series of catches, taken at five levels in a depression 
in Puget Sound 112 fathoms in depth, the conclusion is reached that 
the surface strata present the greatest number of living individuals 
and furnish the most favorable, though irregular, conditions for their 
multiplication. The relative number of living and dead individuals 
changes in going from surface to bottom ; for example, 82 per cent of 
Coscinodiscus in the surface water were alive, but only 29 per cent in 
the bottom water. A great accumulation of this genus in the deeper 
water is explained as the probable result of a previous, but no longer 
continuing, period of rapid growth in the surface water, followed by 
subsidence to the deeper strata. In the case of some diatoms the 
conditions of growth seem to be well fulfilled in the lower strata. 
Indeed, all the organisms of the plankton were found in a living con- 
dition throughout the 112 fathoms, excepting the Copepoda, which 
were not met with below 64 fathoms. Cc. 
Faune de France.?— This is the third volume issued of one of 
those convenient manuals of systematic biology so frequent in the 
Old World and so rare in the New. Would that we had something 
of the sort for other groups than vertebrates! The first volume of 
this Fauna of France dealt with the Coleoptera; the second embraced 
the rest of the Hexapoda. This volume contains the other Inver- 
tebrata, including the Thysanura, which were omitted ftom Vol. ii, 
1 Peck, J. I., and Harrington, N. R. Observations on the Plankton of Puget 
Sound, 7rans. N. Y. Acad. Sci., vol. xvi, pp. 378-387, Pls. XXXVII, XXXVIII. 
2 Faune de France, par A. Acloque, tome iii, 500 pp., 1664 figs., 18 mo. Paris, 
1899. 10 frcs. 
