34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 59 



Since the female of this species closely follows the description and 

 drawings of the male of P. acus, the validity of P. parae Cook, erected 

 with some question as to its distinctness from P. acus, is substantiated. 



A character not noted in the description of P. acus is the presence 

 of slender tubercles that project beyond the margin of the segment 

 just above each posterior leg on segments 2 to 18. The female meas- 

 ures 20 mm in length. 



Family EURYURIDAE 



APHELIDESMUS DIVERGENS Chamberlin 



Plate I, fig. 6 



Aphelidesmus divergens Chamberlin, Bull. Miis. Comp. Zool., vol. 62, p. 249, 

 1918. 



Numerous specimens were collected in Trinidad and Tobago, Feb- 

 ruary 1932. 



The antennae are separated by less than the diameter of one of 

 the sockets. Front of the head conspicuously swollen between the 

 antennae and immediately below them. 



Fig. 18. — Aphelidesmus divergens. Gonopod. 



Segments 2, 3, and 4 with a small but distinct tooth at the anterior 

 corner of each keel. 



Segments coarsely tuberculate along the posterior margin below the 

 keels ; on the anterior segments this tuberculation is not confined to 

 the marginal area alone but extends onto the lateral surface. Anterior 

 corner of the keels, beginning with segment 5, beset with many sharply 

 conic tubercles, as is also the posterior margin of each keel. 



In both sexes there are two conic tubercles on each side of the ster- 

 num opposite each leg with the exception of the first two pairs of 

 legs. 



One of the gonopods is shown in figure 18. 



