226 Mr. R. I. Pocock on neio Geopliilidse. 



GeopMlus alacer^ sp. n. (PI. XII. figs. 11, 11 a.) 



Colour ocliraceous, with pale castaneous head and maxilli- 

 pedes. 



Body moderately robust and not very markedly attenuate 

 towards the posterior end ; very smooth. 



Head longer than wide, wider in front tlian behind, with 

 lightly convex sides and nearly straight anterior and posterior 

 margins, indistinctly and sparsely punctured, and sparsely 

 hairy ; frontal plate indistinctly defined. 



AntenncB of moderate length, hairy, the segments narrowed 

 at the base, the apical segment nearly twice the length of the 

 penultimate. 



Prehasal plate invisible ; hasal jdaie very small, about a 

 quarter of the length of the head, narrower than the first 

 tergite, witli its sides strongly converging, sparsely and indis- 

 tinctly punctured and sparsely hairy. 



Maxillary coxce subquadrate, the pleurje, viewed from 

 below, being very narrow, without chitinous lines, the ante- 

 rior margin bearing two conspicuous teeth ; sparsely punc- 

 tured and hairy ; the feet long, considerably overlapping the 

 head-plate laterally and anteriorly, the joint of the claw being 

 about on a level with the anterior border of the head ; the 

 claw armed basally with a distinct tooth, the femur with a 

 much smaller blunt tooth. 



Tercjites sparsely hairy, those in the middle of the body 

 being obsoletely bisulcate. 



Tracheal sclerites in contact with the tergites and smaller 

 than the prescutal pleural sclerites. 



Sternites without distinct porous area, except those at the 

 anterior end of the body, marked with a median longitudinal 

 groove. 



Anal somite. — Tergite not quite covering the pleura>, 

 smooth, narrowed behind ; pleura moderately inflated, smooth 

 above, furnished beneath with seven large pores, of which 

 the two posterior are the largest ; sternite narrow, longer than 

 wide, its sides posteriorly converging ; prosternal pieces 

 small ; legs a little longer than those of the preceding somite, 

 slender, attenuate, the segments increasing in length from 

 base to apex, aimed with a long claw ; anal pores con- 

 spicuous. 



Number of ])airs of legs 33 in female. 

 Length 21 millira. 



A single specimen from the Straits of Magellan collected 

 by the officers of H.M.S. 'Alert.' 



This species is remarkable for its small number of legs, the 



