578 Hyalella 



Body smooth, long, slender. Side-plates 1 — 4 quadrate. Pleon segments 

 1 — 3, postero-lateral corners acute. Eyes nearly round, dark, approximating 

 above. Antenna 1 nearly as long as antenna 2, flagellura 13-jointed, both 

 antennae shorter in Q than in ö. Gnathopod 2 in d, 6*^ Joint large, widening 

 to the oblique, rather convex palm, which is defined by a projection; 6*^ Joint 

 in § long and narrow. Peraeopods 3 — 5 said to be subequal, but in figure 

 showing the usual successive elougation. üropod 3 very long, extending far 

 beyond the tip of the telson, almost to the end of uropod 2. Telson with 

 2 long setae on bind margin. L. 3 — 6 mm. 



Brazil (near Campos). 



9. H. cuprea (Faxon) 187 6 Allordiestes cup^'eus, Faxon in: Bull. Mus. Harvard, 

 v.S p. 372 f. 32—34 | 1893 Hyalella cujirea, A. Della Valle in: F. Fl. Neapel, u20 

 p. 514 t. 58 f. 1. 



Body stout, smooth. Side-plates 1 — 4 rather deep. Pleon segment 3, 

 postero-lateral corners quadrate. Antenna 1, flagellum about 10-jointed. 

 Antenna 2 considerably longer, about Yg as long as body. Gnathopod 2 

 in ö, 6*^ Joint swollen, palm convex (or, in figure, sinuous), setiferous, 

 oblique, defined by a prominence, finger strong, curved. Gnathopod 2 in 9 , 

 6* Joint long and naiTow. Peraeopods 3 — 5, 2^ Joint large, bind margin 

 slightly serrate. Peraeopod 3 much shorter than peraeopods 4 or 5. Colour 

 in many parts a coppery lustre. L. 9 — 11 mm. 



Lake Titicaca. 



10. H. inermis S. I. Sm. ?1860 Amphithoe andina, A. PHlippi, Reise Atacama, 

 p.l70 1 1888 Hyalella a., T. Stebbing in: Kep. Voy. Challenger, v.29 p. 326 | 1874 H. 

 inermis, S.I.Smith in: ßep. U. S. geol. Surv. Terr. 1873, p.609 1. 1 f. 1, 2 | 1891 H. L, T. 

 Stebbing in: B. Whymper, Trav. Great Andes, p. 361 f.; suppl. p. 125 | 1876 Allorchestes 

 dentatus var. inermis -\- A. d. var. graeilicornis, Faxon in: Bull. Mus. Harvard, v.'S p. 373 

 f.; p. 374 I 1893 Hyalella dentata (pari), A. Della Valle in: F. Fl. Neapel, i;. 20 p. 516. 



Öbdy entirely devoid of dorsal teeth. Appendages as in H. azteca (p. 575), 

 except: Antenna 1 in d reaching middle of flagellum of antenna 2; 3*^ 

 Joint of peduncle fuUy as long as 2^; flagellum longer than peduncle, 

 8 — 10-jointed. Antenna 2, flagellum much longer than peduncle, 12-jointed 

 (in var. gradlicornis Q antenna 2 half as 'long as body, twice as long as 

 antenna 1; flagellum 13-jointed). Gnathopod 1, o*'^ and 6*^ joints stout, 

 6*^ widening to palm, which is defined by a blunt tooth, 6*^ Joint bent 

 down on broad apex of 5*^; gnathopod 2 has the palm nearly straight, 

 without any abrupt notch near the middle; finger slightly curved, terminating 

 in an acute horny tip. L. 4 — 6 mm. 



Colorado; Ecuador; Peru; Argentina; Chili. In pools, lakes (Titicaca), canals etc., 

 also in saline water; to a height of 4053 m. 



11. H. jelskii (Wrzeön.) 1879 Hyale (Allorchestes) j., Wrzeäniowski in: Zool. 

 Anz., V.2 p. 176, 490 | 1888 Hj., T. Stebbing in: ßep. Voy. Challenger, v. 29 p. 1705 | 

 1893 Hyalella j., A. Della Valle in: F. Fl. Neapel, ^20 p. 514. 



Head longer than 1^* peraeon segment. Eyes small, circular. Antenna 1 

 more than half as long as antenna 2, flagellum twice as long as peduncle, 

 with 11 joints in ö and 9 in Q. Antenna 2 in (5 % as long as body, 

 flagellum twice as long as peduncle, with 18 joints; in Q more than ^2 ^^ 

 long as body, flagellum twice as long as peduncle. 14-jointed. Maxiila 1, 

 palp less than ^s distance between its base and apex of inner plate. 



