DECAPODA. 
417 
Tribe A \_Aschizopoda, Westw.]. — Those which, in the proportions, forms, and uses of the feet, the 
anterior, or at least the second, pair being cheliferous, and which carrying their eggs beneath their 
tails, approach the Brachyura, and which are ordinarily known under the names of Lobsters, Cray- 
fish, Prawns, and Shrimps. Divisible into four sections: — 1. Anomala; 2. Locustse; 3. Astacini; 4. 
Carides. 
Tribe B '[Schizopoda, Latr.]. — Those which have the legs slender and filamentous, accompanied by 
an external articulated branch as long as the limbs, which thus appear doubled in number ; fitted for 
swimming, and not cheliferous, the eggs being carried beneath them, and not under the tail. [Opossum 
Shrimps.]* 
The first section [of the tribe Aschizopoda], or the Anomala. — The two or four hind legs are always 
much smaller than the preceding. The under side of the tail never presents more than four pairs of 
appendages, or false legs.f The lateral swimming-pieces at the extremity of the tail, or the parts which 
represent them, are thrown back at its sides, so as not to form with the terminal segment a fan-like 
swimmeret. The ocular peduncles are generally longer than those of the Macroura of the following 
sections. [Two subsections, Hippides and Paguriens.] 
The subsection Hippides (Latr.) has all the upper teguments of the body solid. The two fore-legs 
either terminate in a monodactyle or fingerless hand, like a plate, or they terminate in a point. The 
six or four following legs terminate in a swimming-plate. The two terminal legs are filiform, folded 
back, and situated at the lower base of the tail, which is suddenly narrowed after the first segment, 
which is short and broad, and of which the last is in the form of a long triangle. The lateral appen- 
dages of the penultimate segment are in the form of bent swimming-plates. The sub-abdominal 
appendages are four pairs, and formed of a very slender filiform stem. The antennae are very pilose 
and ciliated, the lateral at first approaching the intermediate, and then being bent outwards. 
Albunea, Fabr., comprises a single species fi’om the Indian Seas {Cancer Symnista, Linn.) 
[a singularly formed animal], with long, setaceous, intermediate antennae ; the carapax flat, 
nearly square, rounded at the posterior angles ; a pair of very compressed, triangular, 
monodactyle fore-legs,— the three following pairs terminated by a flat, sickle-shaped joint. 
Hippa, Fabr., Emerita, Gronovias, has the antennae short, the intermediate with two fila- 
ments longer than the external; the two fore-legs terminated by a very compressed claw, 
without fingers ; the carapax ovoid. Type, Cancer Emeritus, Linn. Indian Seas. 
Reniipes, Latr., differs from the last in the four antennae being very short, and nearly of 
equal length ; the ocular peduncles very short, and in some other particulars. Type, R. 
testudinarius, Latr. From the seas of New Holland. 
The subsection Paguriens has the teguments but slightly crustaceous ; and 
the tail is generally soft, bag-like, and bent. The two fore-legs terminate in a 
didactyle claw ; the four following terminate in a point ; and the four posterior 
much shorter, in a small didactyle claw. The first joint of the peduncle of the 
lateral antennae presents an appendage ending in a point, or in form of a spine. 
These Crustacea (which the Greeks named Carcinion, and the Romans Cancelli) 
part, in empty univalve shells. The tail, except in Birgm, only presents (and that 
in the female alone) three false legs placed on one of the sides, each divided into two filiform villose 
branches. The three terminal segments are suddenly narrowed. 
Birgus, Leach, has the tail solid, suborbicular, with two rows of plate-like appendages on the under side. The 
fourth pair of legs is but little smaller than the preceding ; the two posterior pair are [very small, and] hidden in 
a groove in the extremity of the carapax. The carapax is in the shape of a reversed heart, being pointed in front. 
On account of their large size, the solid consistence of their teguments, and the form of the tail, these Crabs are 
not able to lodge in shells, but must retire to crevices in the rocks, or hide themselves in burrows in the earth. 
live, for the most 
* [It is here proper to observe, tliat in the recent arrangements of 
Milne Edwards and M'Leay, the seventh and last section, Notopoda, 
of Latreille’s arrangement of tlie Brachyura, and his first section of 
the Macroura, Anomala, constitute one of the three primary divisions 
of the Decapoda, forming, as may be readily perceived, the passage 
between the Brachyura and the Macroura ; and, as constantly occurs 
where nature passes from one type of form to another, we find amongst 
these animals some of the most striking anomalies which occur in the 
class — hence the name Anornoura, or anomalous-tailed Crabs — 
which are divided by M. Edwards into two primary sections or fami- 
llies: — 1. The Apterura, or those destitute of a terminal swimmeret, 
including the Dromiens, Homoliens, Raniniens, and Pactoliens ; and, | 
2. The Pterygura, or those which have a pair of moveable appendages 
at the extremity of the tail, including the Porcellaniens, Hippiens, 
and Paguriens. Thus it will appear that the former section is more 
analogous to the Brachyura, and the latter to the Macroura.] 
t With the exception of the anterior pair, these appendages are 
either rudimental or obsolete in the males,— a peculiarity which oc- 
curs also in the Galathaem, Scyllari, and Palinuri. We may also ob- 
serve, that in these three genera, the swimmerets at the extremity of 
the body are more slender, or nearly membranous, at the posterior 
margin. In this section, as in Galathaea, the portion of the thorax 
which supports the hind pair of legs forms a sort of peduncle, whence 
1 this pair of legs appears to be attached to the tail. 
