Hyalella 577 



5. H. latiiuana (Faxon) 1876 Allorchestes latimanus, Faxon in: Bull. Mus. 

 Harvard, v.'d p. 370 f. 27, 28 | 1888 Hyalella l, T. Stebbing in: Rep. Voy. Challenger, 

 «;.29 p.455 i 1893 H. latimana, A. Della Valle in: F. Fl. Neapel, u 20 p. 515 t. 58 f. 8. 



Body thick, peraeon Segments 6 and 7 and pleon segments 1 — 3 each 

 produced to a small medio-dorsal spinifonn tooth. Side-plates 1 — 4 quadrate, 

 their lower angles rounded, side-plate 4 emarginate behiud. Pleon seg- 

 ments 1—3, postero-lateral corners prolonged backward. p]yes nearly round. 

 Antenna 1 % as long as antenna 2, peduncle reaching middle of ultimate 

 Joint of peduncle of antenna 2. Antenna 2 half as long as body, number 

 of joints in flagellum not recorded. Gnathopod 2 in d, 6*^ Joint large, 

 broader than long, widening much to the palm, which is moderately oblique, 

 straight, defiued by a prominent tooth. Gnathopod 2 in 9 much smaller. 

 Peraeopod 5 of moderate length. Uropod 3 reaching a little beyond telson. 

 Telson broad. L. 7 — 12 mm. 



Lake Titicaca. Depth 18 — 36 m. 



6. H. longipalma (Faxon) 1876 Allorchestes longipalmus, Faxon in: Bull. Mus. 

 Harvard, u3 p. 371 f. 29— 31 | 1888 Hyalella l, T. Stebbing in: Rep. Voy. Challenger, 

 «;.29 p.455 | 1893 H. longipalma, A. Della Valle in: F. Fl. Neapel, tJ.20 p. 516 t. 58 f. 9. 



Very near to H. latimana, but peraeon segment 5 in addition having 

 a dorsal tooth. Eyes round, antennae 1 and 2 each with flagellum of 15 joints. 

 Onathopod 2 in (d, 6*^ Joint large and swollen, palm sinuous and very long, 

 setose, so oblique as to leave a very short bind margin, fi*om which it is 

 defined chiefly by impact of finger. Telson with seta on each side of bind 

 margin. L. 9 — 13 mm. 



Lake Titicaca. 



7. H. armata (Faxon) 1876 Allorchestes ar malus, Faxon in: Bull. Mus. Harvard, 

 v.S p. 364 f. 1—18 I 1888 Hyalella armata, T. Stebbing in: Rep. Voy. Challenger, u 29 

 p. 455 I 1893 H. a., A. Della Valle in : F. Fl. Neapel, v. 20 p. 514 t. 58 f. 2, 3. 



Body stout, bind margin of segments raised in conspicuous transverse 

 ridge. Side-plates 1 — 4 produced into spine-like processes (longer in specimens 

 from greater depth), 1^* — 3'^ directed downward and forward, 4*^ about twice 

 as long as 3^, at right angles to length and height of body. Eyes round. 

 Antenna 1, peduncle reaching middle of ultimate Joint of peduncle of antenna 2, 

 flagellum 12-jointed. Antenna 2 much longer than antenna 1, gland-cone 

 prominent, flagellum 13-jointed. Maxiila 1, palp (in figure) reaching more than 

 half the distance from its base to apex of outer plate. Gnathopod 1, 5*^ Joint as broad 

 (in figure broader than and as long) as 6*^, palm ti'ansverse, slightly concave, 

 finger curved. Gnathopod 2 in c? very large, 6*^ Joint widening much to the 

 palm, which is oblique, straight, with small setae, finger sl ender, curved. 

 Gnathopod 2 in 9 smaller, 5*^ and 6*^ joints subequal, palm nearly trans- 

 verse. Peraeopods 3 and 4 apparently with naiTOw 2^ Joint. Peraeopods 4 

 and 5 elongate. Branchial vesicles simple. Marsupial plates long and rather 

 broad, fringed with short setae, apex pointed. üropod 3 very small, curved 

 upward, projecting little beyond the bit)ad telson. Integument with rows of 

 microscopic hairs. L. 7 — 10 mm. 



Lake Titicaca. Depth 20—120 m. 



8. H. longistila (Faxon) 1876 Allorchestes longistilus, Faxon in: Bull. Mus. 

 Harvard, v.3 p. 375 f. 37 ] 1893 Hyalella dentata var.?, A. Della Valle in: F. Fl. Neapel, 

 t!.20 p. 517. 



Das Tierreich. 21. Lief.: T. R. K. Stebbing, Amphipoda I. 37 



