Bibliography. 399 
phitis Americana, or skunk, is found in both Americas, extending from 
the frozen regions of the northern, to Chili and Paraguay in the south- 
ern hemisphere. Lutra Canadensis and Braziliensis, which Dr. De Kay 
regards as identical species, there being no essential differences, extends 
over the immense tract of country lying between the Arctic seas and 
Brazil. 
The number of extinct mammifers whose remains have as yet been 
discovered within the limits of the state, is very small, and even these 
have been detected more abundantly elsewhere. ‘The fossil elephant, 
E. primigenius, has been found in one locality only. The remains of 
the Mastodon giganteum, Cuvier, have been detected in several locali- 
ties ; but since they have not as yet been detected in Massachusetts or 
other eastern states, excepting Connecticut, New York may be regard- 
ed as enclosing a portion of the eastern limit. 
The only other fossil mammiferous remains indicated by Dr. De Kay, 
are those of the fossil stag, Elaphus Americanus, which have not been 
detected except in one or two instances. Jap 
2. Monographies D’Echinodermes Vivans et Fossiles; par Lovis 
Acassiz. Neuchatel, Suisse, 1841 and ’42. 4to, planches.—Our know- 
ledge of the Echinodermata has within a few years been much increas- 
ed, especially by the labors of Muller, Tiedemann and others in Ger- 
many, and by Mr. Forbes in England. The ‘“‘ History of British Star- 
fishes,” by the last named naturalist, although confined to such species 
as are met with on the coast of England, yet may be considered as the 
first work in which an attempt has been made to unite in a single mo- 
nograph all the different orders of the Echinodermata. In the magni- 
ficent monographs now in the course of publication by M. Agassiz and 
his collaborators, are included all the fossil as well as existing species 
hitherto known, illustrated by numerous and well executed plates. No 
effort has been spared to render the descriptions as complete as possible, 
including what has been for the most part overlooked by previous nat- 
uralists, viz. the internal organization. The importance of such a plan 
must be at once apparent, since it should be no less the province of the 
zoologist to ascertain what animals existed on the earth’s surface during 
the early history of the world, than those which are found at the pre- 
sent day, and it is evident that the study of organization will be here- 
after inseparable from the corgect methods of zoological research. 
The first monograph contains descriptions of Salenies, by M. Agas- 
siz; the second, of the Scutelle, by M. Agassiz; the third, Galerites 
and Dysasters, by Desor; and the fourth, the anatomy of the Echinz, 
by G. Valentin. Of the Scutedl@ there are described thirteen genera 
and seventy-four species, illustrated by twenty-five quarto plates, inclu- 
