_ in the discrimination of species and genera, as well as of their vario 
other relations. We should be very glad to see a complete set of 
"DOMESTIC. — 
1. Professor Saved Green’s Monograph of the Trilobites 7 North 
America, with colored models of the species.—The author, in his in- 
troduction, after stating the general characters by which these fossils 
may be recognized, enumerates the genera established by previous 
authors, viz. five genera from Brongniart, one genus from Dr. DeKa 
and three genera from Prof. Dalman. ‘The essential characters of 
all these genera are concisely given, so that those who may wish to 
examine this subject, may do it without resorting to the rare and ex- 
pensive works of the French and Swedish naturalists. A tenth 
genus is here added by Prof. G. to include some curious foreign 
trilobites. A list of all the species heretofore described is then added 
and the introduction closes with some speculative remarks. 
In addition to the ten genera in the introduction, five other genera 
are proposed by the author, all supposed to be peculiar to North 
America; he also noticed two others suggested by Prof. Eaton. 
The species described as natives of North America are thirty three 
in number; twenty two of which are supposed to be now described for 
the first time. ‘The work then terminates with some brief observa- 
tions on the nature of the trilobites, in which there is a notice of a 
recent trilobite, now in the Albany Institute. It is to be regretted 
that that animal has remained so long undescribed. ~ 
~The monograph is admirably illustrated by the colored models, 
done in plaster by Joseph Brano, whose success in this effort, must 
give full confidence that his talents can be advantageously employed 
on other occasions in the service of natural history. 
"\ We are happy to see this application of the art of modelling thus 
favorably introduced into this country ; it must be of great utility to 
= and teachers, as well as to original investigators. Mr. Bra- 
no’s models are beautifully done, and are nebrs2 of the monograph 
“to which they belong. 
Prof. Green appears to us to have executed his work with fidelity, 
ability and good taste, and it cannot fail to aid in promoting our geo- 
logical researches. It is worthy of being mentioned that the mon- 
ograph is got up in a very neat style, and forms a very convenient, 
volume, either for the desk or the pocket. The minute and exact 
_ examinations and descriptions of natural history are very important 
