424 PROCEEDINGS OF THE \ \tl<>\ 1 /. \ll sl'l l/. vol.38. 



Second antenna (fig;. IS//) three - segmented, broad, strong, and 

 dactyl-shaped, its terminal segmenl about twice as long as wide and 

 armed with six strong spines, one of which is situated on the face of 

 the segment, and is somewhat inconspicuous. Mandibular palp (fig. 

 18a) with a two-segmented base, and hearing two bristles at its tip, 

 one plumose and about twice as long as the base, the other longer and 

 simple. 



The maxillipeds are as in fig. 18c. First leg dig. is/") with a 

 basal pari of two broad segments, the first one over three times as 

 broad as long and bearing a semicircular row of spinules at its outer 

 distal margin. Second segment irregular in shape, with a heavy 

 plain spine at each distal angle, and a semicircular row of spinules 

 between the bases of the two rami. Outer ramus three-segmented, 

 and more than twice as long as the inner one, each segment with a 

 large spine on its outer distal angle, and the terminal segment with 

 an extra spine and two slender seta 1 . Inner ramus indistinctly two- 

 segmented, the terminal segment with two strong plain spines. Sec- 

 ond to fourth feet alike, with both rami three-segmented, and with 

 many long plumose seta-. 



Fifth foot (fig. L8« ) slightly longer than wide, and in the form of a 

 plate, with a seta on each lateral margin, which is slightly longer than 

 the foot. Its distal margin is four-lobed, with the deepest indenta- 

 tion in the middle. Basal portion with two semicircular rows of 

 spinules. 



Furcal rami (fig. ISg) slightly longer than wide, each with a \<>\y 

 short inner seta, a dorsal seta, and t wo large terminal seta', the outer 

 of which is about one-seventh as long as the inner and plumose ex- 

 teriorly, while the inner is fully as long as the body, but very slightly 

 spathulate at base, and with very delicate tips. 



Named for \h\ (I. (). Sars. 



I}> minis. This species at fust glance superficially somewhat re- 

 sembles /. natans Williams, but differs markedly in color, in shape of 

 rostrum, size, ami shape of projection of second segment of first an- 

 tenna, character of armature of terminal segment of second antenna, 

 first leg with two terminal seta' and t wo spines, instead of one terminal 

 seta and two spines, comparative lengths of terminal setae of furca, 

 and shape of fifth foot: it having four lobes, which are of different 

 sizes and shapes, instead of being regularb six-lobed. 



Bui four other species of this genus are known to the writer — 

 I. affinis Scotl (Gulf of Guinea), /. coriaceus Brady and Robertson 

 (British seas and coast of France), /. holoihuria (Edwards), and 

 /. nutans Williams (Narragansetl Bay, Mill Cove, Wickford). 



Occurrence. Collected plentifully with a birge net among floating 

 algae in Eel Fond and Little Harbor, Woods Hole, Massachusetts, 

 July, August; alsd brackish ponds. Woods Hole. 



T ; ,pe.— Cat. No. 39512, Q.S.N.M. 



