102 M. E. Claparéde on M. de Quatrefages’s" 
tance to the character of the distribution of the sexes in his 
division of the Vermes into classes. The Oligocheta, setting 
their moneeciousness on one side, are Annelides in every respect, 
and they will remain in that class notwithstanding their monce- 
cious character. On the other hand, the Branchiobdellea are 
identical with the Oligochzta in so many respects, that the re- 
union of the whole series of the Bdellea (7. e. the Hirudinea) 
with the class of Annelida appears to become a desideratum of 
science. 
Having restricted the class Annelida to the group of Annelida 
Polycheta of Grube, M. Quatrefages, like Audouin and Milne- 
Edwards, subdivides them into two orders—the Annelida 
errantia and A. sedentaria. In their general features these two 
orders are very natural; for, under different names, they have 
been admitted by all authors. But the manner in which M. 
Quatrefages characterizes them will give rise to criticisms, be- 
cause it leads to some consequences which are evidently forced. 
Thus he arranges the family Nerinea among the Hrrantia, and 
the Leucodorea among the Sedentaria. Now these two families 
contain worms so closely related to each other that they evidently 
form a single natural family. This is so true, that this family 
has already been established by Sars, who has characterized it 
with much care under the name of Spiodea. The celebrated 
Norwegian naturalist, in the establishment of this family, has 
certainly furnished a fresh proof of the truth of his zoological 
intuition, which has been so often experienced. In a general way 
it is to him that we are indebted for the best recent works on 
the classification of the Annelides,—works which, it is to be 
noped, M. Quatrefages will take more notice of in his work 
than would be supposed from the note which we have before us. 
The best evidence that the distinction between the two families 
Nerinea and Leucodorea rests upon an artificial foundation is 
that the author places Nerine in one and Spvo in the other, er at 
least in an appendix to the other. Now these two genera are 
identical, as has been shown by Sars. That M. Quatrefages had 
good grounds for effecting a separation in the family Ariciea, m 
which Grube placed the Leucodore and the Nerine, few will 
absolutely dispute. But this separation had already been made 
in a very judicious manner. ‘The true distinction to be made is 
that between the Ariciea and the Leucodorea or Spiodea; but 
then we must place in the latter family the genera Spio, Pygo- 
spio, Nerine, and the other Nerinea of M. Quatrefages, including 
the genus donis, which, it may be remarked in passing, appears 
to be founded only on some Nerine with the antenne torn off*. 
* The genus Polydore of Bosc, admitted by Quatrefages, is synonymous 
with Leucodore. 
