60 THE AMERICAN NATURALIST. [VoL. XXXIV. 
ing" will be more favorably received than have been the many 
attempts to find a substitute for the German “ Anlage." 
The verbal nouns referred to must imply such verbs as “to 
inpush " and “to outpush," and these forms are, as a matter of fact, 
employed, as, for instance (p. 19), *becomes inpushed into the 
deeper layers," but upon the same page the expression ‘ pushed 
inside " and also the noun “ingrowth” appear, thus causing some 
confusion. 
A characteristic which impresses one especially favorably is the 
extreme conciseness and concentration shown in the entire work, 
which, at the same time, does not prevent the description from being 
more than usually clear and comprehensive. An especially good 
illustration of this is seen in the morphological description of the 
skull, in which the entire subject is covered within the limits of sev- 
enteen pages, and yet every essential point is fully treated (pp. 150- 
167). 
The second part of the work is called the ** Classification of Ver- 
tebrates," but in reality it gives not only the enumeration of the 
groups, but also presents so many anatomical details that it may be 
used as a special comparative anatomy filled with the details which 
were not possible in the first part. Thus, if a student is in search 
of a special point in the anatomy of any animal, he should first read 
the morphological description of the organ as given in the first part, 
and then turn successively to the descriptions of the class, order, 
and the smaller subdivisions within which the animal in question is 
found. This seems an excellent arrangement and may be the cause 
of the extreme conciseness of the first part, as it avoids clogging the 
exposition, of the theories with concrete examples, as in the majority 
of the text-books on the subject. Especially noticeable in the second 
part is the treatment of the reptiles, which are completed by the 
addition of the fossil orders ; and that of birds, which gives the new 
classification founded upon anatomical characters. 
The work is illustrated by 378 text-figures, of which about 150 
are original and new. 
Recent monographs have contributed several which thus appear 
for the first time in a text-book (Ex. Figs. 120, 139, 160, 161). 
Among the new figures there are some exceptionally clear diagrams, 
such as Figs. 35, 61, 62, 110, and a series illustrating the relation- 
ship of the various cavities of the body (Figs. 111, 127, etc.). 
At places where we are accustomed to meet certain time-worn fig- 
ures there is some relief in finding either a new object employed or, 
