298 
ZOOLOGICAL LITERATURE. 
The second section is on certain particulars concerning AnceuSy 
but appears not to bear very materially upon the subject. 
The third section is on the metamorphosis that the young un- 
dergoes upon its escape from the ovum. The appearance of the 
eggs in the egg-pouch is so immediately after the last ehange, that 
M. Hesse considers that fecundation must have taken place 
while yet the females were in the larval condition. The Praniza 
or female Anceus in its younger stages is more slender, and it 
assumes the niore robust proportions which M. Hesse attributes 
to the adult stage only in proportion to the deyelopment of the 
impregnated ovum, impregnation probably taking place, as 
in the higher forms of Crustacea, after the female has cast its 
exuviae, and previously to the new crust being restored to its 
natural hardness. The eggs are round, and M. Hesse has 
found that the period of incubation lasts from twenty to twenty- 
five days. From the embryonic form he traces the larva until it 
reaches the condition of a creature independent of its parents. 
The fourth section is a description of the young at the period at 
which it changes into Anceus, In this description we take excep- 
tion to the term Praniza being used instead of larva. That 
some of the larvae are young Pranizce, no doubt, is correct ; but 
others, agaip, bear no resemblance to it, so that it is obviously un- 
desirable to make use of the name of Montagues genus to signify 
the young, of which there are evidently two distinct forms, the 
one leading to Anceus male, the other to Anceus female {Praniza ) . 
In this section the animal of Praniza is described in detail. We 
do not think that M. Hesse is correct in saying that the cephalon 
(tete) is distinct from the pereion (corps) , being separated by an 
articulation that serves as a neck. Certainly the first and second 
segments of the pereion, unless the first be altogether wanting, 
are fused with the cephalon. We think the description of this 
section demonstrates the necessity of a clearly defined nomencla- 
ture, homologically uniform and correct. M. Hesse in describing 
the cephalon speaks of the rostruniy which, he says, is formed 
by the oral appendages. 
Now, if a rostrum means anything in carcinology, it means 
the anterior central projection of the carapace to a point ; and it 
is quite clear that the oral appendages, however anteriorly and 
pointedly produced, can never be described as a rostrum without 
risking confusion in anatomical description. 
Section five is a description of the male Anceus y in which 
there are two points that are novel and interesting : the first is 
that M. Hesse has observed, in dissecting the oral apparatus, an 
organ that he thinks may be a sucker \ the second, that there is 
a strong intromit tent organ, attached, by the posterior extremity, 
in the central line of the pereion. 
The sixth section is a description of the female Anceus, which, 
we maintain, differs in nothing, in the several specimens figured 
