No. 418.] NOTES AND LITERATURE. 863 
almost every publication issued, and is a subject worthy of interna- 
tional consideration. Next after the abbreviations we come to a 
systematic index. When we consider that this index of families 
and species occupies not less than sixteen pages in double columns, 
we may begin to comprehend the enormous increase in described 
species during the last few years. All in all, there are probably 
1100 species of Oligocheta now sufficiently well described to be 
readily identified. As is well known, the majority of species of this 
class can only be identified by anatomical characters. This makes 
identification difficult without the aid of illustrations, and it is much 
to be regretted that so few are found in this otherwise so valuable 
monograph. The morphological part is confined to ten pages, and 
it is here that the want of illustrations is especially felt. The author 
introduces a number of new words to indicate structures, such as 
tanilobic, zygolobic, prolobic, etc., according to the various and 
different encroachments of the prostomium on the anterior somite, 
etc. Many of these names have been derived from the Greek and 
Latin and are most happily found, and we can only regret that the 
author has not seen fit to revise also the general nomenclature to 
such an extent that students of other languages could readily under- 
stand what parts and organs are referred to. Why not use, for 
instance, * spermatheca" instead of “ samentasche," etc.? The 
larger part of the book is devoted to a systematic description of the 
species, their genera and families. These descriptions are models 
of conciseness, including all the principal exterior and interior 
Characters necessary to define the species. A large number of 
names have been changed, priority being given to the oldest ones, 
according to the rules adopted by the German society of naturalists. 
In this department the author has made very thoroug 
as a consequence we meet with many novelties which will be referred 
to in their respective places. Every genus is preceded by a key 
for identifying the species. Many will object to the style of key 
opted. In our opinion the most desirable key in all: systeme 
works is the one which, besides facilitating the finding Mite 
Species, at the same time gives us an idea of the systematic arrange 
ment and relationships. The system adopted by the author gives E 
idea of the affinity of the species, but simply facilitates finding tn 
In adopting the present style of key the yste a" né 
genera and species certainly suffers. This is especially the aa 
large genera, as, for instance, Dichogaster (Benham, pun 
the species number over 150. oi n 
