CRUSTACEA. 623 



awl-shaped spines between them. The feet of the CephalotJiorax 

 have a shear-shaped extremity ; in the sixth pair the shear is small 

 and almost concealed by four lancet-formed, horny laminae, 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. BANZANI Osservazioni sul Limulo polifemo in Opuscoli scientifici. 

 Bologna, II. 4to. 1818, pp. 275 285, and VAN DER HOEVEN Eecherches 

 sur VHist. natur. et I' Anatomic 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 LATR., GUERIN Iconogr., Crust. PL 34, fig. i, 

 DESMAREST Crust. PL 51, VAN DER HOEVEN Recherch. PI. 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., BUMPH Amb. Rariteik. 

 Tab. xii., VAN DER HOEVEN 1. 1. PI. I. 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. HOEVEN 1. 1. Tab. v. ; on the coast of Japan. 



* * Att the feet in loth sexes didactylous. 



Sp. Limulus rotundicauda LATR., V. D. HOEVEN 1. 1. Tab. iv. figs, i 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 ; 



