108 



68. Thalestris brunnea, G. 0. Sars, n. sp. 



(PL LXIII). 

 Syn: Thalestris rufociolacens, Brady (not Clans). 



Specific Characters. Female. Body very robust and somewhat depressed 

 throughout its whole length; seen dorsally, slightly tapering behind. Integu- 

 ments coarsely chitinized. Cephalic segment large and broad, occupying rather 

 more than half the anterior division, epimeral parts less deep than in the 3 pre- 

 ceding species; rostral projection strong, deflexed, acutangular at the tip. Posterior 

 edge of this and the 3 succeeding segments minutely crenulated. Urosome some- 

 what exceeding half the length of the anterior division, and slightly narrowed 

 behind, genital segment almost twice as broad as it is long, and, like the 2 suc- 

 ceeding segments, having the lateral edges minutely ciliated; penultimate segment 

 forming a triangular prominence behind, arching over the small last segment. 

 Caudal rami short and broad, densely spinulose at the edges and with the apical 

 setae of inconsiderable length, the innermost but one being about half as long as 

 the urosome. Eye very large and conspicuous in the living animal. Antennae 

 differing but little in structure from those in the other species. Mandibular palp, 

 however, somewhat less fully developed, the basal part being only very slightly 

 expanded distally. Anterior maxillipeds remarkably short and compact, with the 

 innermost lateral lobe rather large, and divided into 2 diverging lappets, each 

 carrying a thickish plumose seta, claw of outermost lobe very strong; terminal 

 part rudimentary. Posterior maxillipeds likewise of an unusually compact struc- 

 ture, basal joint very short, hand much curved outside, palmar edge straight and 

 imperfectly defined in front, terminal claw strong and much curved at the tip. 

 First pair of legs with the outer ramus somewhat longer than the inner, and 

 scarcely narrower, terminal joint armed with 3 unequal claws finely denticulated 

 on the one edge, and moreover, at the inner corner, with a rather long curved 

 seta, and outside the claws with a small spinule; inner ramus, as usual, carrying 

 on the tip 2 claws, which are likewise finely denticulate and somewhat less un- 

 equal than in the preceding species. Last pair of legs of moderate size, extend- 

 ing somewhat beyond the middle of the genital segment, distal joint broadly oval 

 in form and obtuse at the tip, inner expansion of proximal joint rather large, 

 with 2 of the marginal setae considerably produced and spiniform. 



Colour of body, except the dorsal face of the cephalic segment, a deej 

 brown, posterior -edges of the segments still darker. 



Length of adult female about 1 millimetre. 



