instit; 
x sonian ON 
STEJNEGER 
COLLECTION 
National NuseSA7 
PREFACE. 
Tue first Edition of Professor Van per Horven’s manual 
was published in parts between the years 1827 and 1835. 
He undertook the labour, as he informs us, not with any 
desire to add one more to the numerous works with a 
similar title already in existence, which should be neither 
better nor worse than these. On the contrary, if he had 
found any one of them to be a sufficient guide for his 
public teaching, without great alterations, he would have 
abstained from his contemplated task. Accordingly, the 
plan of his work differed from that of most other manuals 
in beginning with the simpler forms of animals, and pro- 
ceeding upwards to the highest: and from that of all of 
them, in embodying a much larger amount of anatomical 
information. His work was received with marked appro- 
bation not confined to the limits of his own country. 
During the lapse of nineteen years, which intervened 
between the first and second editions, the acquisitions 
both of Zoology and Zootomy had been greatly enlarged, 
so that in many departments the former science had 
assumed an entirely new aspect. Consequently the second 
