Kill 



joint of the 3 posterior pairs large and laminar; last pair considerably shurter 

 than the 2 preceding ones. Last pair of uropoda rather small, only slightl}- 

 reaching beyond the preceding pair, rami without any marginal setae. Telson 

 oblong, dee])ly cleft, each terminal lolie with 2 apical denticles. 



Memarlcs. — The present new genus is founded u])on the small Tvvsi- 

 anassid desci'ibed by Prof. Lllljeborg as Anony.r pumilns, wliieh on a closer 

 examination of the anatomical details shows a number of well marked diffe- 

 rences from the 2 preceding genera, so as more properly to be regarded the 

 type of a separate genus. Tlie 2 species described by the writer from the 

 Norwegian North Atlantic Expedition as Anonyx calcarahts and Anony.r 

 tiiphlops would seem to belong to the same genus, as also a 3rd species pro- 

 cured on the same Expedition, which is still more nearly allied to C intmiJus, 

 but which at that time was wrongly confounded with the latter species. The 

 generic name here projiosed refers to the spinifonn jn-oduced last pair of 

 epimeral plates of metasome. 



44. Centromedon pumilus, (Lilljeborg). 



(I'l 34, lig. 2) 

 Anonyx immilus, Lilljeborg, On the Lysianassa magellauica etc., p 26, PI. IV, figs. 35—41. 



Syn: Lysianassa producta, Goes. 



Body very short and robu.st, though somewhat compressed, witli highly 

 curved liack. Cephalon about the length of the 1st segment <if mesosome, 

 lateral corners drawn out to a sharply pointed straight s})ine. Anterior 

 coxal plates nearlj' 3 times as deep as the body and rather narrow, the 3 

 first having each at the infero-posterior corner a small dentiform ])roi ection ; 

 1st "i)air sliglitly tapering l)elow; 4th pair with the posterior expansion rather 

 short and nearly transversely truncated at the tip; 5th pair about as deep 

 as broad. Last pair of epimeral plates of metasome produced at the lateral 

 corners to a sharp u})turned spiniform lobe. First segment of urosome slightly 

 impressed dorsally and having behind the depression a small roTinded carina. 

 Eyes altogether wanting. Superior antennte a little shorter tluin tlie (•c])lialon 

 and tlie 2 fii'st segments of mesosome combined; peduncle not very tumeticated, 

 1st joint about twice the length of tlie otlier 2 combined; Hagellnm scarcely 

 attaining the length of the peduncle and composed of 8 articulations only, 

 the 1st of wliich about equals in length the 2 succeeding ones taken together; 

 accessory appendage half tlie lengtli of tlie flagellum and 3-articulate. In- 

 ferior antennae scarcel\- longci' tlian tlie superior, flagellum !l-articulate. 

 Anterior gnathopoda witli the propodos about the length of tlie carpus, 



