8i>2 ZOOLOGICAL LITERATURE. 
account of tlieir function^ t)iey should be called mdclioires ou 
pattes maclioires/^ If terms are to be altered with every change 
of function^ those by which the parts of a crustacean may be 
known will never be settled. We contend that^ from the highest 
typical species to the most aberrant form^ but one name should 
be the scientific expression of the same part in all, and that the 
least analogical reference the name can bear to that of any 
animal beyond the limits of the class, so much tlie more con- 
venient will it be found in clearness of description. 
Hr. Sars contends that the so-called shell-gland has an inti- 
mate connexion with respiration (a view coinciding with that 
of Ley dig), that its contents are perfectly limpid and free from 
the presence of cellules, and that there are reasons to believe 
that it has some analogy with the aquiferous vessels of the 
Hirudinees and Lombricines. 
The author next treats of the minute structural anatomy of 
the mouth, the salivary glands, the nervous system, and the 
organs of sense. 
He considers that the first pair of antennae represent the 
organs of two senses — one existing in the auditory cilia) which, 
from their resemblance to the same organism in the higher 
Crustacea, he presumes to represent the same sense, and the 
other in some hairs terminating in an extremely fine and 
delicate point ; these, he considers to be organs of touch ; this is 
presumed in consequence of having observed that this form 
of hair in the genus Holopedium is transferred from the first 
pair of antennae, which are protected by a membrane, to the 
second pair, they being the only part of the animal which has 
direct communication with the exterior. 
In treating of the propagation of these animals he differs 
from all authors, and denies that the formation of the ephippial 
ova is common to all the Cladocera, and asserts that they only 
exist in the family of Daphnidcc as defined in his memoir and 
comprising only the old genus Daphnia. He states that at the 
approach of winter certain species of Cladocera are provided 
with winter ova; but these, like the summer ova, are fecun- 
dated, and have their place immediately upon the body of the 
animal, in the great cavity of the shell, called by Jurine the 
matrix. 
In the classification of the Cladocera, the author, besides the 
attention which the structure of the pereiopoda requires, takes 
into consideration many of the particulars of the rest of the 
organization — as, for instance, the arrangement of the very varied 
nervous system, and, which is perhaps the most noticeable, the 
presence or absence of the valves; on these he founds the two 
primary divisions, each of which he subdivides into two tribes, 
dependent upon the structure of the pereiopoda, as follows : — 
