Miscellaneous. 239 
readily give rise to mistakes. Cells of the animal detach them- 
selves from the mass, and remain scattered all round it. Some of 
these are finally dissolved, but others (or, at least, bodies which 
cannot be distinguished from them in appearance) begin to emit 
very delicate transparent filaments, resembling those of Actinophrys. 
Some of these bodies even become encysted in the manner of Actino- 
phrys and Ameba. From these, four or five monociliated Monads 
are sometimes seen to issue: these are capable either of creeping in 
the manner of Ameba, or of swimming by the agency of their flagel- 
lum. These creatures are sometimes present in such great number, 
in the interior of dying Spongille, that one might be led to regard 
them as masses of sponge-cells. We should then have to recur to 
Dujardin’s notion that the Spongille were merely masses of Amebe 
inhabiting a sort of siliceous polypary. M. Lieberkiihn, however, 
shows that these bodies form no integral part of the Spongilla, and 
that they appear also in great quantities in the ova of fishes and other 
animals when in course of perishing. But he does not settle the ques- 
tion whether the Monads are the embryos of these kinds of 4meba, 
or whether we are to consider them as parasites of these parasites. 
It is interesting to compare these facts with the observations made 
by Jeeger upon Hydra. It has been asserted that these animals are 
capable of breaking up into little unicellular Amcebiform creatures, 
which on their part can reproduce the Hydre. Is not this an ana- 
logous case of parasitism misinterpreted ?—Miiller’s Archiv, 1863, 
p- 717; Bibl. Univ. June 20, 1864, Bull. Sci. p. 183. 
On the Geographical Distribution of the Annelida. 
By A. De QuATREFAGES. 
Having completed a work on the Annelida which will form a 
portion of Roret’s Suites a Buffon, M. Quatrefages has communicated 
to the Academy of Sciences of Paris some remarks upon the geo- 
graphical distribution of those animals. He observes that, although 
the imperfection of our knowledge of the species would render it 
premature to undertake any detailed investigation of the subject, it 
is possible to indicate certain general laws, some of which are of the 
more importance as they contrast strikingly with facts universally 
recognized in other groups. His results are as follows :— 
1. The class of Annelida properly so called (Annelida Errantia 
and Tudbicola) isin salt waters the geographical term corresponding to 
the land and freshwater class of Erythreina (Lumbrici and Naides). 
2. The class of Annelida has representatives in all seas. This is 
also the case with the two orders of which it is composed (Errantia 
and Sedentaria) ; in this respect the group under consideration may 
be said to fall under the general rules. 
3. This cosmopolitism appears to extend not only to the large genera 
which best reproduce the general type, but also to the most excep- 
tional subtypes, and even to those genera which might be supposed 
to be most characteristic. In this respect the Annelida differ from 
all the other groups which have been investigated from a geographical 
point of view. 
4, Hence it results that the Annelidan fauna does not appear to 
