100 



Bulletin Vanderbilt Marine Museum, Vol. VI 



tip of the scaphocerite. This length differs somewhat according 

 to sex and age. 



All five pairs of legs have epipodites, but those of the fifth pair 

 are shorter than those of the preceding pair. 



The thelycum is a subcircular plate, composed of two halves, 

 lying side by side, with their inner lateral margins straight, 

 thickened into a lip-like ridge, protruding ventrally and separated 

 from their anterior margin by a narrow, short, median ridge that 

 extends slightly anterior to the circular plate for about one or 

 two millimeters, and continues posteriorly between their inner 

 lateral margins for almost a third of the length of the thelycum. 



Text figure 7 — Peneus merguiensis de Man, petasma of adult male, 

 shown from posterior side. Enlarged. 



The petasma is figured (see fig. 7). It arises about mid- 

 way the inner lateral margin of the peduncular article and con- 

 sists of two plates united to form a tubular organ ; the ventral- 

 lateral margin of each plate is curved and distally rounded ; these 

 tips curve inward to the mouth of a second tube, formed by the 

 ridge of the inner fused margin of the two halves ; the apex of this 

 ridge is produced into a rounded process bent over above the 

 curved ventral apices. 



The male receptacle consists of a median ridge in the anterior 

 of the space between the fifth pair of legs ; this ridge is produced 

 to a ventral median ridge and slopes to either side. Separated 

 from the entire ridge are a pair of plates, one on either side, which 

 project as far forward as the basis of the leg and have the anterior 

 distal border unequally lobate. The space between the fourth pair 



