fi09^ 



Reiiiails. — The present form was first described by Sp. Bate from 

 female specimens as Siplionoecetcs crassicornw, and was subsequently recorded 

 b}^ the author from the Norwegian coast. It is easily distinguished both 

 from the t3'pe species and from the 2 forms described by the Rev. Mr. Steb- 

 bing from the Challenger Expedition, by the comparatively short and stout 

 antennae, and by the peculiar structure of the posterior gnatliopoda in 

 the male. 



Occurrence. — The only place, where I have hitherto met with this 

 peculiar Amphipod, is outside Jsedern, in a depth of 40 — 50 fathoms. The 

 animal inhabits a free, membranous tube of a rather regular, short cylindrical 

 form and open at both ends. When it withdraws itself into the tube, the 

 large basal joints of the superior antennaj close the apertm-e like an operculum. 



Distribution. — British Isles (Sp. Bate). 



Gen. 2. Siphonoecetes, Kroyer, 1845. 



Body slender and narrow, with the metasome and urosome very small. 

 Cephalon but slightly produced in front, lateral lobes narrowly produced between 

 the insertions of the 2 jjairs of antennse. Coxal plates very small, and but little 

 different in size. Eyes more or less developed, placed at the extremity of the 

 lateral lobes of the cephalon. Antennse more or less densely setiferous and 

 rather unequal, the superior ones being comparatively slender, without any acces- 

 sor}' appendage, but with the flagellum well developed, the inferior ones much 

 longer than the sxiperior and also more strongly built, subpediform, with the 

 flagellum rather short and armed at the tip with unguiform spines. Mandibular 

 l)alps small, consisting of only a single joint densely setous at the tip and inner 

 edge. Gnathopoda of the very same structure in the two sexes, and some- 

 what unequal, the posterior ones being considerably stronger than the ante- 

 rior, and distinctly subeheliform. Anterior pairs of pereiopoda with the 

 basal and meral joints much expanded; antepeniiltimate and penultimate 

 pairs comparatively small, and of same structiire, with the dactylus inverted; 

 la.st pair considerably more elongated, and having the basal joint lamellarly 

 expanded, and fringed on both edges with long, ciliated setae. Branchial 

 lamellae of moderate size, wanting at the base of the posterior gnathopoda. 

 Pleopoda Avell developed, with the basal part considerably expanded inside. 

 The 2 anterior pairs of uropoda biramous, with the outer ramus the larger, 

 and spinulous outside; last pair with the basal part larainarly expanded, 



