431 



350 



Fig. 187. Phrosina semilunata Risso (after Bovallius, 1889). 



350 



together and distally slightly broadened; the 5th segment is longer than 

 wide, distally likewise broadened, and the 6th segment articulates with 

 its anterior distal angle to form a subchela with the 5th segment; with 

 a closed subchela the 6th segment projects beyond the posterior distal 

 angle of the 5th segment by a produced denticle; the distal margin of the 

 5th segment is finely denticulate; the claw is rudimentary and conical. 

 Pereopods IV are longer and stronger than pereopods III. Pereopods V 

 are exceptionally well deve4oped and in length comparable to the size 

 of the crustacean itself; the corresponding somite of the pereon is also 

 appreciable longer than the rest. The 2nd segment of pereopods V has 

 a bulged and slightly distally projecting anterior margin; the posterior 

 margin is almost straight; the length of the segment is roughly 1 .5 times 

 its width and less than the total length of the 3rd-5th segments; the dis- 

 tal angles of the 3rd-4th segments is sharply extended below; the 5tli 

 segment is slightly elongated and anteriorly and distally incised with 

 coarse uneven denticles; the 6th segment is almost equal in length to the 

 two preceding segment, narrow, and smoothly curved. Pereopods VI are 

 identical to pereopods V but weaker than they, reaching the end of the 

 5th segment of pereopods V; the 2nd segment is weakly broadened; the 



