SontJi African Crustacea. 69 



the rear. The hands and fingers of the second and third peraeopods 

 are very slender, the movable finger in each case extending somewhat 

 beyond the fixed one. The fifth peraeopod is more slender and much 

 less setose, but longer than the fourth, the difference in length of the 

 fourth, fifth, and sixth joints being very marked, while the fingers 

 are subequal, but the sixth joint in the fifth pair more than twice as 

 long as the finger, in the fourth pair not more than once and a third 

 of the finger's length. 



The petasma, when unfolded and flattened, is seen to consist of 

 two symmetrical conjoint halves, each ending in a rather broad, 

 roughly oval lobe fringed on the outer end with 15 little teeth or 

 spicules and on the inner end with 8 that are blunter but still micro- 

 scopic. Before these transverse overlapping lobes are reached, each 

 division has on its outer (inward folding) side a longitudinal lobe 

 ending obtusely, although a thickening of the otherwise pellucid 

 membrane gives the appearance of an inward curled hook. The 

 second pleopods at the base of the endopod carry a trilobed process, 

 one lobe unarmed extended outwards, the other two downwards on 

 the inner side, one with a furniture of setae, the other with a small 

 fringe of setules. 



Locality. Nicea Eiver, N. by W. 6 miles (near East London) ; 

 depth 50 fathoms. A 1217. 



GEN. PENAEUS, J. C. Fabricius. 

 (See these Annals, vol. 15, pt. 1, p. 12, 1914.) 



PENAEUS SEMISULCATUS, de Haan. 



1849. Penaeus semisulcatus, de Haan, Crust. Japonica, decas 6, 



p. 191, pi. 46, fig. 1. 



1911. ,, de Man, Siboga Exp., vol. 39a, p. 97. 



A specimen 148 mm. in length, witli flagellum of the second 

 antennae 245 mm. long, appears to belong to this species. It 

 has a very small exopod on the fifth peraeopods, and the telson 

 strongly sulcate. The petasma agrees well with that figured 

 by Kishinouye for his P. asliiaka, which Dr. de Man identifies 

 with P. semisulcatus, though not noticing the striking 

 difference in length between the flagella of the first antennae 

 as figured by Kishinouye for both sexes of P. ashiaka and 

 those figured by de Haan for P. semisulcatus. The length 

 represented by de Haan is exceeded by that in our specimen. 



