413 



Pteropsyllus eonsimilis, Scott. 



(Suppl. PI. 38). 



Tetragoniceps eonsimilis, Th. Scott, Additions to the Fauna of the Firth of Forth, Part. VI. 

 12th Ann. Rep. of the Fishery Board for Scotland, p. 244, PI. VII, figs. 412. 



Specific Characters. Female. Body moderately slender, with the anterior 

 division somewhat compressed and about the length of the posterior. Cephalic 

 segment rather large, exceeding in length the 4 succeeding segments combined; 

 rostrum resembling in shape that in the genus Amphiascus, being well defined at 

 the base, slightly curved, and terminating in an acute point. Urosorne somewhat 

 depressed in its anterior part, with the genital segment fully as long as the 

 other 3 combined, 2nd segment with a small appressed spine on each side, last 

 segment rather narrower than the preceding one, but scarcely shorter, anal opercle 

 comparatively small. .Caudal rami narrow linear in form and exceeding in length 

 the anal segment, tip slightly dilated and armed at the outer corner with a strong 

 spine, apical setse rather slender and of normal structure. Anterior antennae 

 about equalling in length the cephalic segment, and 8-articulate, 1st joint much 

 elongated and somewhat tapered distally, with the inner edge finely serrate, 2nd 

 joint scarcely half as long and having the inner distal corner conically produced, 

 terminal part only slightly longer than the 2 preceding joints combined. Posterior 

 antennae with the distal joint very narrow and having the apical setae unusually 

 short, outer ramus forming a very small knob-like prominence tipped with a delicate 

 seta. 1st pair of legs with the outer ramus shorter and much narrower than the 

 1st joint of the inner, resembling in structure that in Tetragoniceps; 1st joint of 

 inner ramus slightly dilated, and carrying inside near the end a slender seta, last 

 joint longer than the middle one, and both combined not attaining half the length 

 of the 1st, apical spine and seta rather slender. The 3 succeeding pairs of legs 

 with the outer ramus comparatively narrow and without any setae inside, inner 

 ramus with the proximal joint somewhat dilated and carrying inside a well-devel- 

 oped seta, distal joint scarcely longer and linear in form. Last pair of legs very 

 large, extending to the end of the 2nd caudal segment, proximal joint short, forming 

 inside a conical expansion furnished with 3 or 4 short setae, distal joint foliaceous, 

 oblong quadrangular in form and somewhat obliquely truncated at the end, which 

 carries 3 short, thick setae, and in the middle 2 juxtaposed small hair-like 

 bristles, outer edge of the joint having a single small seta about the middle. 



Male smaller than female and more regularly attenuated behind. Anterior 

 antenna? hinged in the usual manner. 1st pair of legs with the spine inside the 

 2nd basal joint remarkably produced, sabre-like; inner ramus apparently com- 

 posed of only 2 joints. Last pair of legs very small, each forming an undivided 



55 Crustacea. 



