100. 



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

 than the 2 preceding ones. Last pair of uropoda rather small, only slightly 

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

 oblong, deeply cleft, each terminal lobe with 2 apical denticles. 



Remarks. The present new genus is founded upon the small Lysi- 

 anassid described by Prof. Lilljeborg as Anonyx pumilus, which 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. The 2 species described by the writer from the 

 Norwegian North Atlantic Expedition as Anonyx calcaratus and Anonyx 

 typhlops 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. puni'ilus, 

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

 generic name here proposed refers to the spiniform produced last pair of 

 epimeral plates of metasome. 



44. Centromedon pumilus, (Lilljeborg). 



(PI 34, fig. 2) 



Anonyx pumilus, Lilljeborg, On the Lysianassa inagellanica etc., p 26, PI. IV, figs. 3541. 



Syn: Lysianassa proclucta, Goes. 



very short and robust, though somewhat compressed, with highly 

 curved back. Cephalon about the length of the 1st segment of mesosome, 

 lateral corners drawn out to a sharply pointed straight spine. Anterior 

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

 first having each at the infero-posterior corner a small dentiform projection; 

 1st pair slightly tapering below; 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 upturned spiniform lobe. First segment of urosome slightly 

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

 Eyes altogether wanting. Superior antennas a little shorter than the cephalon 

 and the 2 first segments of mesosome combined; peduncle not very tumeficated, 

 1st joint about twice the length of the other 2 combined; flagellum scarcely 

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

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

 accessory appendage half the length of the flagellum and 3-articulate. In- 

 ferior antennae scarcely longer than the superior, flagellum 9-articulate, 

 Anterior gnathopoda with the propodos about the length of the carpus, 



