CRUSTACEA. 665 



Peduncle of lateral antennae entirely covered by a large scale. 

 Body compressed, with post-abdomen incurved. Integuments thin, 

 almost membranous. 



Acetes EDW. Maxilliform feet in two pairs. Only four pairs of 

 feet of trunk, the last two pairs being deficient; all filiform, long, 

 none didactylous. 



Sp. Acetes indicus EDWARDS, Ann. des Sc. nat. xix. 1830, p. 350, PI. xi. 

 fig. i. 



Sergestes EDW. Maxilliform feet in two pairs. Feet of trunk 

 in six pairs, filiform, slender, last pair very small, none didactylous. 

 Sp. Serg. atlanticus MILNE EDWARDS, Ann. des Sc. nat. xix. PI. x. fig. i. 



Penceus FABR, Feet slender, furnished with a palpiform lamel- 

 lose appendage at the base ; three anterior pairs armed with a small 

 didactylous chela. Lateral antennae very long. Shell carinate. 



Sp. Penceus sulcatus, Palcemon sulcatus OLIV., EDW. Hist. nat. des Crust. 



PI. 25, fig. i ; Penceus trisulcatus LEACH, DESMAR. Crust. PI. 39, fig. 3 



Penceus setiferus, Cancer setiferus L., SEBA Thesaur. in. Tab. 17, fig. 2 

 (copied in Encycl. meth., Crust. PI. 291, fig. 2) &c. 



Add genera : Sicyonia EDW., Euphema EDW., Stenopus LATR., 

 Aristeus DUVERNOY. 



Ephyra Eoux. 



Pasiphcea SAVIGNY. (In these and the following genus only two 

 anterior pairs of feet are didactylous.) 



Oplophorus EDW. 



Palcemon DALD., FABR. Middle antennae superior, with three 

 setae. Shell carinate in the middle, keel produced anteriorly into 

 a recurved serrated rostrum. Feet of trunk in five pairs, without 

 palp or lateral appendage ; two anterior pairs didactylous. 



Sp. Palcemon squilla FABR., Cancer squilla L., BASTER Natuurk. Uitspann. 

 II. Tab. in. fig. 5, GUERIN Iconogr., Crust. PI. 22, fig. i ; the prawn 

 (steurTcrab, crevette, salicocque) &c. A fossil species, from the lithographic 

 stone, Palcemon spinipes, of which BAJER (Oryctogr. Norica. 1758, Tab. 

 vin. Suppl. fig. 9) and WALCH and KNORR have given figures, the last of 

 which is copied by DESMAREST Crust, fossiles, Tab. xi. fig. 4, appears to 

 stand between Palcemon and Sergestes and has long spines on the fore feet. 



Add genera : Pandalus LEACH, Lysmata Risso. 



