PRIODESMUS, A NEW GENUS OF DIPLOPODA FROM 



SURINAM. 



By O. F. Cook. 



The specimen on wbicli this description is based came into my pos- 

 session abonttwo years ago, and seems to represent a new generic type. 

 That the species is also new, 1 have not the same degree of confidence, 

 for there are a large number of very poorly described South American 

 Polydesmoidea in the literature of the Diplopoda. However, none of 

 the- descriptions seem to accord with the i)resent form, nor even to 

 approximate it. I noticed nothing closely comparable among the older 

 types in the British Museum, nor is there anything of the kind among 

 the Petersian types of the Berlin Museum. There is, however, in the 

 Berlin IMuseum an undetermined female specimen from Para which is 

 certainly generically the same, and may possiblj' prove to be-specifically 

 identical, for a satisfactory knowledge of the secondary sexual charac- 

 ters of the genus is impossible until more specimens have been obtained. 



PRIODESMUS, iiew genus. 



Rhachidomorpha, Peters, proparle, not of Saussure, 



Body rather small. 



Antennte with four olfactory cones. 



Segments dorsally thickly beset with small and large granules. 



Lateral carina) of moderate width, the margins deeply incised-dentate. 



Repugnatorial pores 11, dorso-lateral, on capitate jirocesses of seg- 

 ments 5, 7, 9, 10, 12, 13, 15-19. 



Penultimate segment not specially shortened. 



Last segment triangular, the apex rounded. 



Sterna of legs 3-6 of males, each with two conic j)rocesses; other 

 sterna unmodified. 



Male legs slightly crassate, the third joint of legs 1-7 inflated on the 

 ventral side. 



The following more detailed description is given: 



Body rather small, about nine times as long as broad, sides i^arallel 

 to near the ends; cavity circular. 



Vertex granular, sulcus evident; post-antennal depression moderate; 

 sense organ large; margin not excised. 



Proceedini;9 of the United States National Musevim, Vol. XVIII— No. 1037. 



53 



