Hyalella 579 



Gnathopod 1 as in H. dybowskii, except that 6^^ Joint is only -/s as long 

 as 5*^ Gnathopod 2 in d, 5*^ Joint ^j.^ as long as 6*^, palm rather oblique, 

 spinöse, finger with ^3 of its length on inner surface of band wben closed. 

 Gnathopod 2 in 9, 6*^ Joint 2^/2 times as long as broad. Peraeopods 1 

 and 2 subequal. Peraeopod 4 slightly longer than peraeopod 5. Accessory 

 branchiae on gnathopod 2 and peraeopods 1 — 3 successively longer, on 

 peraeopod 4 longest and double, on peraeopod 5 wanting. L. 9 4, d 5 mm. 



East slope of Cordilleras (Pumamarca). Height 2511 m. 



12. H. dybowskii (Wrzeäu.) 1879 Hyale (Allor ehestes) d., Wrzeäniowski in: 

 Zool. Anz., V.2 p. 199 [ 1888 H. d., T. Stebbing in: ßep. Voy. Challenger, ».29 p. 1705 | 

 1893 Hyalella d., A. Della Valle in: F. Fl. Neapel, ».20 p. 514. 



Head as long as peraeon segment 1. Eyes oval, widened below. 

 Antenna 1 little more than half as long as antenna 2, peduncle % as long as 

 flagellum, which has in d 13, in 9 10 joints, most of them with a couple 

 of sensory filaments. Antenna 2 half as long as body, peduncle % as long 

 as flagellum, which has in d 15, in 9 14 joints. Maxiila 1, palp about ^/g 

 as long as distance between its base and the apex of outer plate. Gnatho- 

 pod 1, 5*^ Joint as long as 6*^, 6*^ narrow at base, front margin convex, 

 bind concave, palm ti'ansverse, with 2 not very prominent rounded lobes, 

 finger shorter than palm. Gnathopod 2 in d, 5*^ Joint as long as 4*^ half 

 as long as 6*^^, 6*'^ triangulär, palm 73 as long as the Joint, rather oblique, forming 

 a Single curved lobe, finger passing its apex only between 2 palmar spines 

 on to surface of Joint. Gnathopod 2 in 9 like gnathopod 1, but more slender, 

 6*^ Joint small, not twice as long as broad. Peraeopod 1 considerably shorter 

 than peraeopod 2. Peraeopods 4 and 5 equal. Simple tubulär accessory 

 branchiae on peraeopods 1 — 5. 



West slope of the Cordilleras (Pancal, Montana de Nancho). Height 2196 m. 



13. H. lubomirskii (Wrzesn.) 1879 Hyale (Allor ehestes) l, Wrzeöniowski in: 

 Zool. Anz., v.2 p. 177 [ 1888 H. l, T. Stebbing in: Rep. Voy. Challenger, u29 p. 1705 | 

 1893 Hyalella l, A. Della Valle in: F. Fl. Neapel, u 20 p. 514. 



Head as long as peraeon segment 1. Eyes rather large, irregularly 

 oval. Antenna 1 half as long as antenna 2, flagellum not twice as long as 

 peduncle, 10-jointed. Antenna 2 little over half as long as body, flagellum 

 more than twice as long as peduncle, 18-jointed. Maxiila 1, palp less than Y, 

 distance between its base and apex of inne;* plate. Gnathopod 1 as in 

 A. jelskii, but 6*^ Joint almost as long as 5*^ Gnathopod 2 in d, ö*'^ Joint 

 less than ^g as long as 6*^, palm rather oblique, spinöse, forming 2 lobes, 

 finger with apex only on inner surface of band. Gnathopod 2 in 9 , 6*'^ Joint 

 not quite twice as long as broad. Peraeopod 1 a little shorter than peraeo- 

 pod 2. Peraeopod 4 longer than peraeopod 5. Accessory branchiae simple, 

 quite rudimentary on gnathopod 2, very small on peraeopods 1 and 2, longer 

 than the principal branchiae on peraeopods 3 — 5. L. 5 — 6 mm. 



West slope of Cordilleras (Pacasmayo). Height 2511 m. 



14. H. meinerti Stebb. 1899 H. m., T. Stebbing in : Tr. Linn. Soc. London, 

 ser. 2 V.7 p.407 t. 32 b. 



Side-plates 1 — 3 deeper than broad. Pleon segment 3, postero-lateral 

 Corners acutely quadrate. Eyes blaclc, usually wider apart than the diameter. 

 Antenna 1 slender, more than half as long as antenna 2, 3*^ Joint nearly as 

 long as 2^, but much resembling joints of flagellum, flagellum with 9 or 10 



87* 



