from the Bay of Biscay. 161 



Ant. 1 longer than the head, reaching to the fourth joint of 

 the flagellum of ant. 2 ; first joint considerably longer than 

 second and third united and not much wider than the 

 second, the upper margin of which is produced almost to the 

 end of the third ; flagellum to peduncle as 7 : 5, with ten 

 joints, the first as long as the next three united, setose. 



Ant. 2 : peduncle reaching to the seventh joint of the 

 flagellum of ant. 1, last joint slightly longer than the pre- 

 ceding, with its extremity a little dilated and truncate ; 

 flagellum long and slender, reaching to the end of the pleon, 

 with numerous short joints, naked. 



Gnathopocls and their side-plates as in M. carinatus, Bate. 



First and second peraeopods with the dactyli almost as long 

 as the sixth joints ; third and fourth pair have the dactyli 

 relatively longer. The fifth are broken in all the specimens. 



Uropod 1 : peduncle much shorter than the subequal rami, 

 spinulose ; a few spinules on the outer margin of the outer 

 ramus. 



Uropod 2 : peduncle subequal to inner ramus, outer shorter, 

 bcth smooth ; a few spinules on outer margin of peduncle. 



Uropod 3 : wanting in the seven specimens examined. 



Telson in a young male rounded at the end, with two 

 setules rather close together at the tip. 



Length of adult male 7 mm. Only males were taken. 



A specimen was sent to M. Chevreux in 1899, and he 

 informed me that he considered it to be without doubt the 

 male of his species. Unfortunately it is one of those brittle 

 forms that easily lose their appendages, so that a full and, 

 accurate description is impossible. Thus all the perasopods in 

 M. Chevreux's single specimen and the fifth pair in all mine 

 were mutilated, and the third uropods in both cases entirely 

 wanting. I agree with M. Chevreux that they are the same 

 species, though the (presumably) sexual differences are con- 

 siderable, the most conspicuous and unusual being the promi- 

 nent arcuate carina on the fourth pleon segment, as well as 

 on the third, in the male. M. Chevreux's specimen was taken 

 in the u Gulf of Gascony " at a depth of lhO metres. It 

 may be mentioned that the so-called tubercle on the second 

 joint of the peduncle of ant. 1 in the male is a prolongation of 

 the upper margin of the joint and not of the lower as shown 

 in M. Chevreux's figure. It is not easy to see till the 

 antenna is separated from the head. 



