505 



408 



Fig. 219. Oxycephalus clausi Bovallius. 



with it, but ventraily transits abruptly. In large females the head is ovate 

 and the height 1/2-2/3 its length; the rostrum constitutes 1/3 the length 

 of the head and merges smoothly with it. In males dimorphism is not 

 manifest, although sexual maturity is attained at highly varying sizes. 



The 2nd segment of pereopods I has convex margins and is shorter than 

 the distal part of the leg; the 5th segment is broad, being broadest in the distal 

 409 part. A morphological detail characteristic of the species and differentiating 

 O. clausi from the closely related O. piscator is the sharply projecting and 

 slightly stretched anterior distal angles of the 5th segment and sometimes 

 with seta located at its base. The pointed process of the posterior margin of 

 the 5th segment is finely denticulate on the outer margin and more coarsely 

 so on the inner margin; the 6th segment is shorter than the 5th and has a 

 strongly bulged anterior margin and straight denticulate posterior one; the 

 claw is small and barely curved. The 2nd segment of pereopods II is shorter 

 than the rest of the leg and has a barely bulged posterior margin; the 5th 

 segment, without the process, is longer than wide; the anterior distal angle 



