FBESH-WATEK CrOLOPID^ AND CALANIDiK, 81 



in size from the first to the fifth, which last is scarcely wider than 

 the first abdominal segment. First abdominal segment rather 

 tumid in front, nearly as long as the following three segments, 

 and bearing on each lateral margin in front of the middle a stout 

 seta : borders of the abdominal segments smooth, except the 

 last, which is finely pectinated ; caudal rami slender, elongated, 

 parallel, or slightly divergent, about five times as long as broad, 

 lateral setse short, considerably removed from the apex ; at the 

 anterior third, on the outer aspect of the ramus, is a transverse 

 row of several short setae, and the inner margins are minutely 

 ciliated ; the outer and inner tail-setse are very short, the outer 

 rather the shorter of the two ; of the two median setae the inner- 

 most is the longer, equalling in length the entire abdomen ; both 

 are minutely ciliated. Anterior antennae shorter than the first 

 body-segment. All the swimming feet have both branches three- 

 jointed ; the outer branch of the first foot has at the apex of the 

 last joint a single spine and a seta, and on the outer margin one 

 spine ; the remaining feet have the same apical armature, but 

 have two lateral spines. The feet of the fifth pair are two- 

 jointed, the basal joint rather wide and bearing at the distal 

 angle one long seta, second joint long and narrow and bearing 

 two apical setae, one as long as the joint itself, the other more 

 than twice as long. Length 1'55 mm. 



The only British locality known to me for this species is 

 Duddingston Loch, Edinburgh, where it was found by Mr. 

 Thomas Scott, P.L.S., of the Scottish Fishery Board. On com- 

 paring these British specimens with American ones, kindly sent 

 to me by Mr. B. "W. Thomas, I cannot find any great difference. 

 The antennae in the latter are perhaps somewhat longer. 



It is with considerable doubt that I have admitted C. Thomasi 

 as a distinct species. Probably Herrick may be right in looking 

 upon it as a mere variety of the preceding. Hoek, in his figure 

 of the caudal rami of C. bisefosus, gives the characteristic basal 

 row of setae, though very feebly developed. 



