98 Ampeliscidae, Ampelisca 



without a lens-shaped thickening of its coruea; sometimes ocular pigment 

 present without lenses. Antenna 1 attacbed at apex of head, without accessoiy 

 appendage; antenna 2 far back below. Upper lip helmet-shaped, minutely 

 incised; lower lip 4-lobed. Mandible (Fig. 28), maxillae 1 and 2, maxillipeds 

 with all the normal parts well developed. Inner plate of maxilla 1 sometimes 

 without setae, sometimes with 1 or 2. Base of maxillipeds fringed with 

 feathered setae and the outer plates armed with sti'ong spine-teeth on inner 

 margin. Gnathopods 1 and 2 imperfectly subchelate, the 5*^ Joint never sh orter 

 than the 6*^; gnathopod 2 longer and more slender than gnathopod 1 (unless 

 Ampelisca australis be an exception). Peraeopods 1 and 2 (Fig. 22) with 

 4*^ Joint very large, usually longer and more setose in peraeopod 1 than in 

 peraeopod 2, 7^^ Joint slender, elongate. Peraeopods 3 and 4, 2*^ Joint very 

 broad, ö^^^long and strongly spined, 6^^ and the minute T^h retroverted. Peraeo- 

 pod 5 (Fig. 23, 26, 27, 29) unlike the preceding, varying in the different genera. 

 Branchial vesicles transversely pleated. Cleft ot telson (Fig. 24) generally very 

 deep, sometimes minute. Antennae 1 and 2, uropod 3 generally, and occasionally 

 peraeopod 5 and telson vary in the two sexes. Glutiniferous apparatus extensive. 



Marine. 



3 genera, 40 accepted and 7 doubtful species. 



Synopsis of the genera: 



Peraeopod 5 (Fig. 23, 26), 2d joint without setae 

 between its expansion and the 3d Joint, öth 



foliaceous, 7tb lanceolate 1. Gen. Ampelisca . p. 98 



Peraeopod 5 (Fig. 27, 29), 2<i Joint with setae 

 I between its expansion and the 3<i Joint, öth 

 ' narrow, 7th spiniform — 2. 



j Peraeopod 5 (Fig. 27), 2d Joint much widened 



2 J distally 2. Gen. Byblis . . . p. 111 



( Peraeopod 5 (Fig.29), 2d Joint not widened distally 3. Gen. Haploops . . p. 116 



1. Gen. Ampelisca Kr0yer 



1842 Ampelisca (Sp. un.: A. eschrichtii), Kreyer in: Naturh. Tidsskr., vA p. 154 | 

 1888 A., T. Stebbing in: Rep. Voy. Challenger, v.29 p. 1035 ] 1891 A., G. 0. Sars, Crust. 

 Norway, v.l p.l64 | 1893 A. (part.), A. Della Valle in: F. Fl. Neapel, 17.20 p. 469 | 1846 

 Ampelisia (laps.), Kreyer in: Voy. Nord, Crust. t. 23 f. 1 ] 1853 Pseudophthalmus, 

 Stimpson in: Smithson. Contr., v. 6 nr. 5 p. 57 | 1853 Araneops, A. Costa in: Rend. 

 Soc. Borbon., n. ser. v.2 p. 169 | 1856 Tetromatus, Bäte in: Rep. Brit. Ass., Meet. 25 

 p. 58 I 1857 T., Bäte in: Ann. nat. Hist., ser. 2 v. 19 p. 139 | 1887 Amplisca (laps.), 

 Chevreux in: Bull. Soc. zool. France, v. 12 p. 574. 



Head with postero-antennal corners obsolete. Side-plate 1 scarcely deeper 

 than 2*^, offen concealing base of antenna 2 ; side-plate 4 with rare exceptions 

 (as A. odontoplax), obliquely truncated below the posterior angle (Fig. 25). 

 Corneal lenses 4 or none. Mandibular palp with 2'^ Joint generally laminar, 

 3* linear and rather short. Peraeopods 3 and 4 with 2'* Joint veiy broad, its 

 front edge strongly curved in the middle, 5*^ Joint caiTving a simple series 

 of spines within the hinder margin. Peraeopod 5 (Fig. 23, 26), 2*^ Joint 

 variously expanded so that the greatest breadth is sometimes lowest (transversely 

 truncate), sometimes more or less median (obliquely ti-uncate), the margin 

 forming the lower side of the triangle being fringed with plumose setae; the 

 following joints varying much in relative size, the 6^^ foliaceous, the 7*'^ lanceolate. 

 Uropod 3 (Fig. 24) reaching considerably beyond the others, rami foliaceous. 



