DR. G. S. BRADY ON DIAPTOMUS SANCTI PATRICII 1 69 



pair of legs much dilated, and having its outer margin pro- 

 duced into a strong hook-like process ; inner branch short, 

 distinctly bi-articulate, not much more than half as long as 

 the first joint of the outer branch, the median joint of which 

 terminates as usual in a strong claw-like process ; last joint 

 very small, reaching only about one-fourth as far as the 

 terminal claw. Ovisacs large, rounded, and containing a 

 small number of ova — usually six or seven. 



Male. — Somewhat more slender than the female. Right 

 anterior antenna considerably dilated in the middle, tenth 

 and eleventh joints each bearing a small spine on the outer 

 margin, thirteenth joint small and unarmed, fourteenth with 

 a very large and strong spine, the three following joints 

 (15-17) much dilated and bearing a few strong hairs and 

 denticles, antepenultimate and terminal segments simple, 

 filiform, devoid of lateral prominences. Last pair of legs 

 large, the right much the larger of the two, its inner ramus 

 simple, digitiform, much shorter than the terminal joint of the 

 outer ramus, the distal joint of which is more than twice as 

 long as broad, has a long spine attached near the middle of 

 its outer edge, and a long simply curved apical claw ; left leg 

 extending somewhat beyond the two proximal joints of the 

 right leg, the second joint wide, its inner margin very tumid 

 but without any distinct angle ; and bearing in addition to the 

 simply curved, elongated terminal joint, an additional very 

 short laminar appendage, which is not more than half as long 

 as the terminal joint. Length of the body slightly less than 

 that of the female. 



In the original description of D. Sancti Patricii\ suggested 

 that its nearest described relative was probably D. laciniatus 

 Lilljeborg. This was a mistaken view, D. laciniatus being 

 separable from it at a glance by the " laciniated " character of 

 the posterior body segments. The species which most nearly 

 approach D. Sancti Patricii are D. gracilis and D. graciloides : 

 from the former it is distinguished by the strongly spined 

 right anterior antenna of the male, which is likewise destitute 



