10? 



wholly absent. Epimeral parts of the 3 succeeding segments rounded otf. 

 Tail composed in female of only 3, in male of 4 segments. Caudal rami not 

 much produced, in some cases very short, with all the setae originating from the 

 end. Anterior antennae resembling in structure those in the other Ascomyzontidoe^ 

 though having the number of joints somewhat reduced; those in male distinctly 

 hinged and provided with supplementary sesthetasks. Posterior antennae of the 

 usual appearance. Oral cone, however, rather peculiar and somewhat similar to 

 that in the next family, being produced into a very narrow, more or less curved 

 siphonal tube. Mandibles without any palp, and having the masticatory part 

 extremely slender, setiform. Maxillae with the lobes very unequal in size, each 

 carrying 3 setse. Maxillipeds comparatively slender, with the dactyli exceedingly 

 narrow, that of the anterior ones distinctly biarticulate. Natatory legs well 

 developed, with the rami comparatively broad and equal-sized; their armature 

 differing slightly from that in the other genera. Last pair of legs of moderate 

 size, biarticulate, proximal joint broadly expanded inside, distal joint lamelliform. 

 RemarJcs. This genus was established by Giesbrecht, to include the 

 form at first described by Scott as Acontiophorus elongatus. The differences of 

 this form from the true Acontiophori have been duly pointed out by Giesbrecht. 

 Indeed, the only character by which it seems to approach that genus, is the 

 structure of the siphon. Otherwise it agrees fairly well with the other Ascomy- 

 zontidce, and of course ought to be included in that family as here defined. In 

 addition to the type species described below, Giesbrecht records another nearly- 

 allied form from the Bay of Naples under the name of S. longifurca. 



62. Scottocheres elongatus, (Scott). 



(PI. LXVI). 



Acontiophorus elongatus, Scott, Ann. & Mag. Nat. Hist., Ser. 6, Vol. XII, p. 145, PI. IX, 



figs. 1520. 



Specific Characters. Female. Body comparatively narrow and elongated, 

 with the anterior division oblong in form, greatest width scarcely exceeding half 

 the length. Cephalic segment of moderate size and obtusely rounded in front, 

 without any trace of a rostral projection below. The 3 succeeding segments 

 gradually diminishing in size, with the epimeral parts not very prominent. Tail 

 scarcely exceeding half the length of the anterior division ; genital segment com- 

 paratively large, occupying more than half the length of the tail, and somewhat 

 dilated in its anterior part, with a slight prominence on each side, just in front 

 of the genital orifices; anal segment very small, scarcely half as long as the 



