592 THE AMERICAN NATURALIST. [VoL. XXXII. 
was prepared primarily for the use of the students of the University 
of Pennsylvania, and was not placed on general sale, its use was 
greatly restricted. The present edition has been brought up to date, 
and its preparation was one of the last works of the author, the pref- 
ace bearing the date 1897. Among the changes of interest, we note 
the inclusion of not only Balanoglossus but Cephalodiscus and Rhab- 
dopleura in the chordates ; the recognition of Paleospondylus and 
the Astracopphri as cyclostomes and the rehabilitation of the Stego- 
cephali. The work will long remain a necessary assistant to every 
student who wishes to really study vertebrates. One may differ with 
the author upon minor points of his system, such as the retention of 
his groups Rhachitomi and Embolomeri ; with the exclusively osteo- 
logical basis of his classification, which, however, was a necessity in 
dealing with fossil forms, or with the outrageous forms, — carbonic, 
cumbric, etc., adopted for the geological periods ; but when all 
this fault is found there remains behind a work of which any one 
might be proud. 
The introduction to the volume consists of a short sketch by Pro- 
fessor Osborn of the life and the works of Professor Cope, present- 
ing in clear form the many advances both in knowledge of fact and 
in generalization which we owe to America’s greatest comparative 
anatomist. 
Packard’s Text-book of Entomology.’ 
new text-book of entomology appears at a most opportune time. 
The influence of the book because of the kind of entomology it illus- 
trates and illumines will be very great and very valuable. As a 
reference and text-book of the morphology, physiology, and develop- 
ment of insects, it takes for these lines of study that position of 
authoritative and indispensable guide which Comstock's Manual takes 
for the study of the taxonomy and “life-history” of insects. With 
these two manuals of insect study, the English-speaking students of 
entomology are better provided with book guides than are the stu- 
dents of any other country. 
Because there are hundreds of thousands of insect species, and 
because the finding and setting in order of species was the first busi- 
ness of naturalists, most entomologists have given most of their 
time to helping in this business of species finding and distributing. 
14 Text-book of Entomology, repay! the Anatomy, Physiology, Embryology, 
and Metamorphoses of Insects. By A. S. Packard, M.D., Ph.D. The Macmillan 
Co., New York, 1898. 8°, pp. xvii, i with 654 figs. $4.50. 
