ORDER PCECILOPODA. 
361 
Limulus, Fab. 
The species of which have received in trade the name of the 
Molucca-crab. The body, suborbicular, a little elongated, 
and narrowed posteriorly, is divided into two parts, covered 
by a solid testa of two pieces, one for each division, very 
hollow underneath, and presenting above, two longitudinal 
furrows, one on each side, and a keel at the middle of the 
back. The first piece of the testa, or that which covers the 
front of the body, is much larger than the other, forms a large 
semi-lunar buckler, with an edge, supporting on its upper 
part two oval eyes with very numerous facettes, in the form of 
small grains, situated one on each side, on the external side 
of a longitudinal keel, and at the anterior extremity of that of 
the middle, which is common to the two pieces of the testa, 
two small simple eyes approximated together. These keels 
are armed with some teeth, or sharp tubercles. The duplica- 
ture of this testa forms, underneath, at its anterior extremity, 
a plane border, or reflected edge, very much arcuated, and 
terminated interiorly by a double arch, advanced like a tooth 
at the centre of re-union. Immediately below this projection, 
in the concavity of the buckler, is a small inflated labrum, 
carinated in the middle, terminating in a point, and above 
which are inserted two small antennae, in the form of small 
didactylous claws, and elbowed in the middle of their length, 
at the junction of the first articulation, and of the follow- 
ing, or of the forceps properly so called. Immediately under- 
neath, are inserted and approximated by pairs, upon two lines, 
twelve feet, of which the first ten, the anterior two or four of 
the males alone excepted, are terminated in a didactylous 
forceps, while their radical articulation is advanced inte- 
riorly, in the manner of a lobe, furnished with small spines, 
and performs the office of a jaw. The size of these feet in- 
creases progressively. If we except those of the fifth pair, 
