CRUSTACEA. 623 
awl-shaped spines between them. The feet of the Cephalothoraa 
have a shear-shaped extremity ; in the sixth pair the shear is small 
and almost concealed by four lancet-formed, horny lamine, that 
are provided on the outside with a projecting ridge. Below on the 
abdominal shield are six pairs of leaf-shaped natatory feet, of which 
the first pair is the largest, and almost entirely covers the rest on 
the inferior surface ; the five following bear on their dorsal surface 
the gills, which consist of many plates. 
Above, on the shield of the Cephalothorax, are situated two 
kidney-shaped compound eyes, very remote from each other, and 
more forward and near the middle, close to each other, two very 
small simple eyes of an oval form. 
Comp. Ranzani Osservazioni sul Limulo polifemo in Opuscoli scientifici. 
Bologna, 11. 4to. 1818, pp. 275—285, and VAN Der HoEvEN Recherches 
sur l Hist. natur. et VAnatomie des Limules. Avec 7 planches. Leide, 1838, 
folio. 
a) Abdominal shield with last marginal tooth elongate, with apex in the 
middle. 
Feet of the second pair alone monodactylous in males. 
Sp. Limulus Polyphemus Larr., GuéR1IN Iconogr., Crust. Pl. 34, fig. 1, 
DESMAREST Crust. Pl. 51, VAN DER HOEVEN Recherch. Pl. vi. (on the 
eastern coast of America, especially of N. America). 
b) Abdominal shield with last tooth scarcely longer than the rest, broad, 
with sharp point marginal. 
* Feet of the second and third pair monodactylous in males. 
Sp. Limulus moluccanus, Polyphemus gigas LaM., RumpH Amb. Rariteik. 
Tab. x11., VAN DER Horven 1. 1. Pl. 1. The Cancer perversus or Balancas; 
this species is found on the shores of the islands of Sunda and Molucca ; its 
Malay name is Mimie. The Limuli live constantly in pairs, and are also 
sold in pairs. In the months of July and August they are daily taken in 
quantities near the roads of Batavia, and brought alive to market. The 
Malays eat the eggs with avidity, and the flesh also is agreeable to them 
and to the Chinese. These animals can live more than a day out of water ; 
when laid on the back they are not able to right themselves. The tail is 
a powerful instrument of defence. 
Limulus longispina V. D. Horven 1. 1. Tab. v.; on the coast of Japan. 
** All the feet in both sexes didactylous. 
Sp. Limulus rotundicauda Latr., V. D, Horven 1.1. Tab. rv. figs. 1—3. 
East Indies. 
Note.—Limulus virescens LATR. The species appears to me doubtful. A 
single specimen mutilated and imperfect is preserved in the Paris Museum ; 
