NEW CRUSTACEAN OF THE GENUS MYSIS. 327 



cies in rock pools, at Falrnoutli, and these were described the fol- 

 lowing year by Mr. K. Q. Couch, who had taken them at Pen- 

 zance.* These six representatives of the genus, together with 

 that now to be characterized, may be divided into two sections, 

 as follows : — 



A. — Telsoii (central lamina of the tail), luith the apex bifurcate. 



Mysis fiexuosus, Mtiller; My sis LamorncB, R. Q. Couch; My sis 

 Spiritus, n. s. 



B. — Telson (central lamina of tail), ivith the apex entire. 



My sis vulgaris, J. V. Thompson; Mysis Oheron, R. Q. Couch; 

 Mysis Griffi^thsice, Bell; Mysis productus, Gosse. 



It will be necessary, in order to draw attention to the distin- 

 guishing characteristics, to describe here the species of the first 

 section : — 



Mysis flexuosus, MiXller. (PI. XVII., figs. 2, 3.) 



Cancer flexuosus, Muller. Zool. Dan., vol. iv., p. 34, Tab. LXVI- 



Mysis spinulosus, Leach. Linn. Trans., xi., p. 350; Desm. 

 Consid., p. 242; M. Edw. Crust., ii., p. 457. 



Praunus flexuosus, Leach. Ed. Encyc, vii., p. 401. 



Mysis Chamceleonj J. V. Thompson. Zool. Researches, p. 28, 

 Tab. XL, figs. 1—10. Bell Brit. Crust., p. 336; White Pop. 

 Hist. Brit. Crust., p. 143. 



Mysis Leachii, J. V. Thompson. Zool, Researches, p. 27. 



Mysis albescens, cinereus, viridis aut brunneus. Thorax cylindricus. 

 Abdomen a thorace ad caudam gradatim diminuens. Appen- 

 dix antennarum squamiformis oblongo-lanceolata apice oblique 

 truncate, spina ad marginis extei^ioris apicem munita; apex 

 margoque interior dense ciliati, margo exterior sine ciliis. 

 Thoraces frons rostrata ; rostrum breve, obtusum, vix tertiam 

 oculorum partem superans. Oculi appendicis antennarum 

 tertiam vix cequant. Antennae pralongce. Telson fsive 



* The Zoologist, vol. xiv. (1856), p. 5281—5288. 



