394 Brachyuropus, Macrohectopus 



than peimltimate, flagellum 8-jointed. Gnathopod 1 as in B. grewingkii; 

 gnathopod 2 sraaller. narrowing less, palm (in tigure) shorter than bind margin. 

 Peraeopod 3 not miich shorter than the body. Uropods I and 2, rami scantily 

 fringed with setae. üropod 3 less tban ^/g,, as long as body, outer ramus 

 2 — 3 times as long as inner, both having only apical setae. Telson two- 

 pointed, i. e. with acute angles to tbe eraarginate apex. Colour whitish or 

 yellow, L. 32 mm. 



Lake Baikal. Depth 200—500 m. 



16. Gen. Macrohectopus Stebb.*) 



1874 Constantid (non A. Adams 1860, Mollusca!), Costantia (lups.), B. Dybowsky 

 in: Horae 8oc. ent. Koss., <;. 10 suppl. ]>. 50. 51, 18H j 1888 Costantia, T. Stebbing in: 

 Kep. Voy. Challenger, v. 29 p. 427, 428. 



Peraeou smooth, pleon carinate. Head not rostrate. Side-plates all very 

 small and shallow, apparently the 2<* deepest, the 6*^^ widest. Antenna 1 longer 

 and stronger than antenna 2. pedunele very long, 3^ Joint longest, accessory 

 flagellum wanting. Mouth-parts (so far as known) as in Gammarus (p. 460). 

 Gnathopods 1 and 2 slender, feebly subehelate, 5*^ Joint longer than 6*^. 

 Peraeopods 1 — 5 very slender, peraeopod 4 much the longest, 2^ Joint 

 little expauded. üropod 1 much the longest. Uropods 1 and 2, outer ramus 

 much shorter than inner, üropod 3. rami long, lanceolate, equal, 1-jointed, 

 fringed with plumose setae. Telson long, divided. 



1 species. 



1. M. branickii (Dyb.) 1874 Constantia h. -\- C. h. var. akxandri, B. Dybowsky 

 in: Horae 8oc. ent. Ross., i\ 10 suppl. [>. 18H t. 3 f. 7; p. 187 t. 3 f . 6 | 1888 Costantia b., 

 T. Stebbing in: Rep. Voy. Challenger. n 29 i). 1696 \ 1893 Pontogeneia (pari.).?, A. Della 

 Valle in: F. Fl. Neapel, »;.20 p. 891. 



Body slender. Pleon segment 1 with weak median carina running out 

 to a long, horn-like, upward projectiug and slightly forward bent tooth (in 

 mr. akxandri directed straight backward). Pleon segments 2 and 3 with 

 median carina rauch stronger, but tooth directed straight backward and 

 insignificant. Head, front somevvhat depressed. 8ide-plates so small and 

 shallow that the branchial vesides and marsupial plates in a lateral view 

 are exposed. Pleon segments 1 — 3, postero-lateral corners (in figiire) rounded. 

 fjyes rather large, narrowly reniform, black. Antenna 1 about ^:^ as long as 

 body, flagellum shorter than pedunele, witB 23 — 56 joints. Antenna 2 veiy 

 slender, ultimate and penultimate joints of pedunele long, subequal, flagellum 

 with 12 — 22 joints, setiferous as in antenna 1, Gnathopods 1 and 2 subequal, 

 5^^ Joint almost twice as long as Q'^^ (in figui'e subequal to it), 6*^ Joint 

 narrowly oval, palm feebly defined. Peraeopod 1 rather longer than peraeo- 

 pod 2. Peraeopods 3 — 5, 2<^ Joint short, narrow, not setiferous on bind margin. 

 Peraeopod 4, 4 times as long as peraeopod 3, and twice as long as peraeopod 5. 

 üropod 1 reaching beyond üropod 3. pedunele long, but inner ramus longer, 

 5 times as long as the outer (in tigure of var. alexandn shorter than pedunele 

 and not much over twice as long as the outer ramus). üropod 2, inner 

 ramus about twice as long as outer, with plumose setae on inner margin. 

 Colour pellucid. L. o 36 mm. 



Lake Baikal (only met with swiuiming). 



*) Nom. nov. MoKpög long, Jktoi;, sixth, ■nobc^, foot. — The name Constantia is 

 preoccupied (1860, A. Adams in: Ann. nat. Hist., ser.S v.b p. 300). The name Costantia 

 is an accidental misspelling. 



