522 



APPENDIX. 



AMPHIPODA. 



HYP ERIN A. 



HYPERIIDjE. 



{Vol. II. p. 18.****) 



Genus THEMISTO. (Guerin.) 



Themisto. Gttkrin Meneville, Mem. de la Soc. d'Hist. Nat. de Paris, iv. 

 1828. Edwards, Ann. des Sci. Nat. xx. p. 393. Hist, des 

 Crust, iii. p. 84. Spence Bate, Cat. Amph. Brit. Mus. p. 311. 



Generic character. Cephalon transversely ovate. Perion not dis- 

 tended. Pleon slender. Eyes occupying the entire cephalon, dor- 

 sally separated. Antenna? short ; superior pair having the flagellum 

 cylindrical and uniarticulate ; inferior pair more slender, and having 

 the flagellum multiarticulate. Mandibular having an appendage. 

 First pair of gnathopoda short, with the inferior angle of the carpus 

 not anteriorly produced ; second pair having the inferior angle of 

 the carpus anteriorly produced. First two pairs of the pereiopoda 

 having the carpus dilated, the propodos cylindrical, and the 

 dactylos inflected back against the carpus. Third pair of pereiopoda 

 extremely long, being twice the length of the preceding pair, and 

 armed anteriorly with a series of comb-like seta?. The last two pairs 

 of i>ereiopoda not half the length of the preceding. Three poste- 

 rior pairs of pleopoda being long. Telson single. 



