Occasional Papers of the Museum of Zoology 79 



29, Fig. 20J.) Anal valves margined. Anal scale triangular, 

 a tubercle on each side of caudal angle. (PI. 29, Fig. 208.) 



Gonopods of male as shown in PI. 29, Fig. 209. 



Length, 10 mm.; width, 1.3 mm. 



British Guiana: Second iMourie. Aug. 20, 1914; F. j\I. 

 Gaige. Two males collected among the dead leaves on the 

 ground in a tree clump. 



Sand Hill Forest, on headwaters of Hubidibu Creek. Aug. 

 26, 1914; F. M. Gaige. Three smaller females taken in sandy 

 forest floor. 



Holotype, M. C. Z.. 5.183. 



Cyrtodesmidae 

 Cliodesmus, gen. nov. 



Btjdy composed of head and twenty segments. 



Collum narrow, not covering the head abo.'e. 



Second tergite much wider, the keel expanded, its anterior 

 border carried forward. Caudal margin of keel of second and 

 third segments with a projection above a transverse furrow 

 into which the edge of the succeeding keel lits. Keels of seg- 

 ments in general bent downward at outer ends, the ectal mar- 

 gin rounded and crenate. An*^erior and posterior margins 

 entire. Dorsum strongly arched. Each metatergite with two 

 transverse rows of large tul)ercles, the collum with three; no 

 granules or setae. Pores on upper part of anterior slope of 

 keels except on segments fifteen to nineteen, where they have 

 shifted to the outer slope; present on segments five, seven, nine, 

 ten, twelve, ihirteen, and fifteen to nineteen. 



Nineteenth segment extending completely over the twen- 

 tieth, its keels meeting behind as in Cyrtodesmus, etc. 



Coxae of male gonopods large, concealing the telopodite. 



Genotype. Clhdcstuus cryptopygus, sp. nov. 



