522 APPENDIX. 
AMPHIPODA. HYPERIUDA. 
HYPERINA. (Vou. ID, p. 18.****) 

—— 
wa 
Genus—THEMISTO. (Guerin.} 
Themisto. Gufrix Monevinur, Mém. de la Soc. d’Hist. Nat. de Paris, iv. 
1828. Epwarps, Ann. des Sci. Nat. xx. p. 393. Hist. des 
Crust. iii. p. 84. Spence Barr, Cat. Amph. Brit. Mus. p. 311. 
Generic character. Cephalon transversely ovate. Perion not dis- 
tended. Pleon slender. [yes occupying the entire cephalon, dor- 
sally separated. Antenne short; superior pair having the flagellum 
cylindrical and uniarticulate ; inferior pair more slender, and having 
the flagellum multiarticulate. Mandibule 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 sete. The last two pairs 
of pereiopoda not half the length of the preceding. Three poste- 
rior pairs of pleopoda being long. ‘Telson single. 
