610 



terminal joint small, simple, setiferous. Telson imperfectly defined from the 

 last segment, smooth above, and broadly rounded at the tip. 



Remarks. This genus was established in the year 1845 by Kroyer, 

 to include an arctic species, S. tijpicus. It is intermediate between Cerapus 

 and CoropJmim, resembling the former in the general habitus, but agreeing 

 somewhat more closely with the latter in the structure of the several appen- 

 dages. From both genera it may be readily distinguished by the very much 

 elongated inferior antennae and by the rather different structure of the 

 gnathopoda. The genus comprises as yet only 3 species, 2 of which belong 

 to the fauna of Norway and will be described below. 



2. Siphonoecetes Colletti. Boeck. 



(PI. 218, fig. 1). 



Siplionoecetes Colletti, Boeck, Crust, amph. bor. & arctica, p. 258. 

 Syn.: Sipbonoecetes mucronatus, Metzger. 



Body slender, depressed, nearly linear in form, with the metasome 



and urosome very small and combined occupying only YS of the length of 



the body. Cephalon produced in front to a short, acutely triangular rostral 



projection, lateral lobes much produced, and somewhat tumefied at the tip. 



Coxal plates edged with slender bristles; 1st pair angularly produced in 



front; the 3 posterior pairs rather broad in proportion to their depth, and 



having the anterior lobe somewhat larger than the posterior. Eyes well 



developed, rounded, with dark pigment. Superior antennae considerably 



exceeding half the length of the body, and reaching beyond the penultimate 



peduncular joint of the inferior ones, joints of the peduncle nearly of equal 



length, flagellum not attaining half the length of the peduncle, and composed 



of 7 articulations. Inferior antennas very much elongated, about equalling 



in length the whole body, the last 2 joints of the peduncle nearly equal-sized, 



flagellum much shorter than the last peduncular joint, and composed of only 



3 articulations, the last 2 very small. Anterior gnathopoda with the propodos 



about the length of the carpus, and conically tapering distally, lower 'edge 



armed with 3 strong spines. Posterior gnathopoda rather strongly built, with 



(he basal joint comparatively short and thick, meral joint produced at the 



end below to an obtuse setiferous prominence, carpus having below a very 



narrow lobe armed with a strong spine and several slender bristles, propodos 



large and oval in form, with the palm quite short, and the hind margin 



