272 
ZOOLOGICAL LITERATURE. 
that were taken. They consisted of nine species of seven genera, 
of which five had not previously been recognized as British. 
These were : Evadne polyphemoides (Leuckart), Ichthyophorba 
denticornis (Claus), Ichthyophorba angustata (Claus), Dias lon- 
giremis (Lilljeborg), Phaenna spiniferal (Claus). Mr. Brady 
considers Diaptomus longicaudatus of Lubbock to be identical 
with Temora finmarchicay Gunner. 
In this Report his list differs materially from that presented 
to the British Association in the previous August, the nomen- 
clature being adopted from the recent work by Claus. 
In the same Report there is a short communication on the 
* Pycnogonoidea * by Mr. Hodge, who says that only two species 
were obtained, Pycnogonum littorale and Phoxichilidium petio- 
latum, and of these but two or three specimens of each. 
BRACHYURA. 
In Sillim. Amer. Journ. 1863, vol. xxxvi. p. 233, and in the 
^ Annals of Natural History^ for January 1864, p. 16, there is a 
short communication by Professor Dana on the homological 
relation of the various parts of the Insects to those of the Crus- 
tacea. This paper is intended as an explanation to a note (p. 193 
in the twelfth volume of the latter journal) which is appended to 
an article (by the same author) on ceplialization. 
The author illustrates his idea by a diagram, and contends 
that in Insects there are eighteen somites, instead of thirteen as 
commonly received, of which six belong to the head, three to 
the thorax, and nine to tlie abdomen ; that in Crustacea there 
are twenty-one, of which nine belong to the cephalon, five to the 
pereion, and seven to the pleon. In arriving at this conclusion 
in Crustacea, his data are di’awn from the highest Decapoda 
only. 
It is not without surprise that even in this order we find that 
Prof. Dana can di*aw the inference that the gnathopoda, or first 
two pairs of appendages of the pereion, belong to the head, simply 
because they are closely attendant upon the mouth. Surely the 
appendages hold the same anatomieal position in the lobster as in 
the crab, and in the prawn as in the lobster ; yet we see them 
gradually changing their appearance until they are uniform in 
character with the pereiopoda. Dissection demonstrates, even in 
the crab, that they are attaehed to the first two somites of the 
pereion \ and we have the strongly expressed evidenee of the 
separation of the cephalon from the pereion, and the pereion 
from the pleon, in the progressive development of the young 
animal. In the cephalon the new appendages produced after 
the larva has quitted the ovum are posterior to the mandibles, 
and anterior to the gnathopoda. Those which belong to the 
pereion are developed posterior to the two pairs of gnathopoda. 
