Occasional Papers of the Museum of Zoology 45 



a row of larger tubercles along anterior and posterior margins 

 and tubercles of similar size in intervening space not serially 

 arranged ; on each side an area of granules or tubercles ele- 

 vated above margin proper. 



Each ordinary metazonite with dorsal surface densely 

 granular and with three transverse series of larger tubercles, 

 the three series equally developed. Along the lateral margin 

 of the keel a series of much larger rounded tubercles giving 

 the appearance of a fine or less even serration. Pore removed 

 from margin by a distance of from one and a half to two 

 times the diameter of its rim. 



Cauda subquadrate, broader than long, a little narrower 

 at base than in middle of its length, the sides and the caudal 

 margin being weakly convex. 



Gonopods of male with two distal branches, these smooth 

 and unl)ranched, the lower (posterior) one much shorter, 

 curling dorsad distally, the larger branch curling into a circle 

 and in situ resting against the sternite of the sixth segment. 

 See further, PI. 18. Figs. 117, 118. 



Length, male, 70 mm. ; w'idth, 12 mm. 



British Guiana: Labba Creek Sand Hills; July 27, 1914; 

 F. M. Gaige. One male and one female. 



Two males and tw^o females taken at Cacao Plantation 

 about camp in rotten wood, July 16 and 17, 19 14; F. M. Gaige. 



One adult and several immature specimens from bank of 

 Demerara River collected in a very damp and much decayed 

 stump; July 17, 1914; F. M. Gaige. 



Holotype, M. C. Z., 5,127. 



I adoi)t for the genus of this species the name Rhyphodes- 

 mus, although the species on which Cook baged his brief diag- 

 nosis of the genus has not as yet been described and cannot 

 be determined from the published data. 



