132 Messrs. Brady and Robertson on Marine 



flagelliform appendage ; that of the male much swollen, the 

 last joint forming a sort of claw in front of the large vesiculi- 

 form swelling. Mandibles bearing a small one-branched (?) 

 palp. Second pair of maxillipeds setose on the anterior margin, 

 terminating in a long and slender claw. Inner branch of the 

 first pair of swimming-feet nearly twice as long as the outer, its 

 first joint longer than the entire outer branch ; second joint 

 short. Fifth pair of feet well developed, biarticulate in the 

 female ; in the male uniarticulate, much broader, rounded and 

 fringed with shorter and stronger spines. Length -^ of an 

 inch. 



This species was taken plentifully in a pool above high- 

 water mark on the shore south of Clifden in Connemara. 



Genus Idya, Philippi. 

 (Tisbe, Lilljeborg.) 



Idya furcata (Baird). 



Extremely common in littoral situations on weeds ; also 

 taken in the surface-net in sheltered bays. 



Genus Westwoodia, Dana. 



1. Westwoodia nob His (Baird). 



On weeds in Ventry Bay, taken by Mr. E. C. Davison. 



2. Westwoodia minuta, Claus. 

 Dredged in Westport Bay ; rare. 



Genus Ilyopsyllus, nov. gen. 



(l\vs, mud ; \^vXKus, a flea.) 



Corpus tumidum, gibbosum. Antennae anticae brevissimae, appen- 

 diceal ensiformem gerentes, 5-articulatae, parte basali magnopere 

 dilatata ; antenna? posticae validse, ramo secundario carentes. 

 Mandibular parvulae, palpo simplici bisetoso. Pedes primi pans 

 valide armati, ramo interno 1-, externo 3-articulato ; sequentium 

 parium rami ambo 3-articulati. Abdomen breve, versus extremi- 

 tatem attenuatum ; setae caudales spathulatae. 



Ilyopsyllus coriaceus, n. sp. PI. IX. figs. 1-5. 



Body very tumid ; seen laterally the ventral line is almost 

 straight, the dorsal excessively arched, so that the cephalo- 

 thorax forms almost a semicircle ; seen from below, the outline 

 is like that of a spear-head rounded off in front; greatest 

 width situate in the middle, and equal to half the entire length 

 of the body ; posterior half abruptly tapered. First cephalo- 

 thoracic segment very large, forming half the length of the 



