262 
CRUSTACEA. 
two feet; thefirst ten, with the exception ofthe two anteiTor ones in the 
males, are terminated by a didactyle forceps, and inserted, as well 
as the two that follow, under a large semi-lunar shield ; the latter 
have the sexual organs attached to them, and the form of large 
leaflets, as in the case with the ten following, which are branchial 
and inserted under a second shell, terminated by a very hard, ensiform 
and moveable stylet. They are wandering animals, and form the 
genus 
Li M ULUS, Fab. 
The species are known in commerce by the name of the Molucca 
Crab. The suborbicular, slightly-elongated, and posteriorly narrowed 
body is divided into two parts, invested by a solid shell composed of 
two pieces, one to each part, very hollow beneath, and presenting 
above two longitudinal sulci, one on each side, and a carina on the 
middle of the back. The first part of the shell, or that which covers 
the fore-part of the body, is much larger than the other, forms an 
extensive semi -lunar shield, with a reflected edge, furnished above 
with two oval eyes of numerous facets, resembling granules, one on 
each side, exterior to a longitudinal carina ; and on the anterior ex- 
tremity of the middle one, and common to both pieces of the shell, 
two small, closely approximated, simple eyes*; these carinae are 
armed with teeth or acute tubercles. The duplicature of this shell 
at its anterior extremity, beneath, forms a level border, strongly 
arcuated, and terminated interiorly by a double arc, projecting like 
a tooth toAvards the centre of union . Immediately under this projec- 
tion, in the cavity of the shield, is a small inflated labrum, carinated 
in the middle, and terminating in a point, above which are inserted 
two little antennae, in the form of small didactyle forceps, flexed into 
an elbow in the middle of their length, at the point of union between 
the first joint and the second, or of the forceps properly so styled. 
Directly beneath, inserted and approximated by pairs, and on two 
lines, are twelve feet, the ten first of which, the two or four anterior 
ones of the males excepted, terminate in a didactyle forceps ; their 
radical joint, projecting inwards like a lobe and covered with points, 
performs the office of a jaw. The size of these feet augments pro- 
gressively ; those of the fifth pair excepted, they are all composed of 
six joints, the moveable toe of the forceps included. The latter have 
an additional joint, and also differ from the preceding ones by having, 
at their external base, a bi-articulated appendage, directed back- 
wards, the last joint of which is compressed and obtuse ; by their 
fifth joint being terminated on the inner side by five small, moveable, 
horny, narrow, elongated and pointed leaflets, and by the two toes 
of the forceps being moveable or articulated at base. The two pieces 
situated between these feet, which M. Savigny considers as the 
ligula, appear to me to be merely two maxillary lobes of these 
organs, but detached or free. The pharynx occupies the interval 
included by all these feet. The males are distinguished from the 
* One on each side of the tooth that terminates this earina. 
