142 THE ZOOLOGIST. 
PepIpaLps.—See MAXILLIPEDES. 
Prvurz.—The peaked, lower lateral edges of the somites in the Macroura. 
Rosrrum.—The spine, promiuence, or sword-like projection of the anterior 
portion of the carapace. 
Sera.—The hair-like processes of the exoskeleton. 
Somrres.—The divisions, or segments of the head, body and tail. 
Srernum.—The chest, or under portion of the cephalothorax. 
SwimmeRuts.—The abdominal appendages, used for swimming in the 
Macroura, and generally for the protection (in the females) of ova and 
ZoeR. 
Tait.—The anal portion of the abdomen. 
TrLson.—The middle terminal plate or plates of the tail in the Macroura, 
and some of the Anomoura, which enclose the anal orifice. 
Trercum.—The upper or back part of the somite. 
Wrist.—The joint next the hand. 
Zorx.—The larval form of Crustacea. 
Although we have only alluded in a superficial manner to the 
characteristic points in the structure of the Stalk-eyed Crustacea, 
yet we venture to think it will be sufficient to enable the student 
to identify parts or limbs when peculiarities of form connected 
therewith call for description or reference in future observations 
on genera or species. It is not necessary for this purpose to touch 
upon the internal structure, on which, indeed, an entire volume 
might be written, and which would be of no utility in a paper 
treating of methods of identification by means of skeleton-structure 
and external form. 
The first lesson in the study of this class of animals should be 
to procure a perfect specimen of, say, the common Lobster, 
Homarus marinus, or of the river Crayfish, Astacus fluviatilis ; 
then, taking Professor Huxley’s book, ‘The Crayfish,’ as a guide, 
dissect and clean the exoskeleton, attaching, to a board neatly 
covered with black or French-grey paper, each part, limb, 
appendage, or segment, placed a short distance apart, but in 
their relative positions; then, with a fine brush and a little 
pigment, place a small number close to each part; each number 
should correspond to one, either on a reference table at the foot 
of the board, or in a note-book. This table or note-book should 
contain full descriptions of the various articulations, which will 
become soon familiar to the student by thus practically working 
out the specimen. 
(To be continued.) 
