AMPELISCA, 
125 
AM PHI POD A, 
NATATORIAL 
A MPELISGIDES. 
Genus — AMPELISCA. Kroyer. 
Ampelisca. 
Araneops. 
Pseudophthalmus. 
Tetromatus. 
Kroyer, Nat. Tidskr. 1 ser. iy. p. 154, 1842. Spence 
Bate, Ann. Nat. Hist. ser. 2, vol. xx. p. 255. Oat. 
Axnph. Brit. Mus. p. 90. Liljeborg, Ofvers. af 
Kongl. Yetensk. Akad. 1851, p. 22 ; 1855, p. 137. 
Costa, Rend, del Accad. del Sc. di Nap. 1853, p. 169. 
Stimpson, Marine Invert. Grand Manan. Proc. Nat. H. 
Soc. Boston. 
Spence Bate, Brit. Assoc. Rep. 1855, p. 58. Ann. Nat. 
Hist. ser. 2, xix. p. 139. White, Hist. Brit. Crust, 
p. 171. 
Generic characters. Cephalon produced, and tapering an- 
teriorly- Eyes four, simple, two situated on each side, near 
the extremity of the cephalon. Superior antennae at the ex- 
tremity of the cephalon, without secondary appendage. Inferior 
antennae placed very far posteriorly to the superior. Mandibles 
having an appendage. Gnathopoda imperfectly subchelate. Pos- 
terior pair of pleopoda biramous. Telson squamiform, cleft. 
The animals of this very curious genus have the body 
long, smooth, and more compressed anteriorly than pos- 
teriorly, so much so that the anterior portion of the 
dorsal surface presents a wedge-shaped appearance, but 
scarcely carinated. The head gradually tapers in front 
to an obtuse point, at the extremity of which the su- 
perior antennae are situated. The eyes are placed near 
the extremity of the head, and consist of two small 
simple organs upon each side, four in all, whence the 
generic name “ Tetromatus we had proposed, at the 
suggestion of our excellent friend, Mr. Adam White. 
The superior antennae are without a secondary append- 
