184 Dr. W. T. Caiman on new 



the brush of haira on the third uropods of the male are the 

 most conspicuous. The first of these and the absence of the 

 endopod of the third uropods are characters equivalent to 

 some that are used in other families of Gammaridea for the 

 separation of genera ; but there is as yet no necessity to give 

 them generic value in this case. 



Order ISOPODA. 



Suborder Flabellifera. 



Family Sphaeromidae. 



I follow Hansen (Quart. Journ. Micr. Sci. (n. s.) xlix. p. 98, 

 1905) in placing Limnoria in a subfamily, Limnoriinoe, of 

 the Sphaeromidse instead of in a separate family. A trivial 

 modification in Hansen's definition of the subfamily is re- 

 quired by the fact that the fifth pair of pleopods in the new 

 species are not entirely without marginal setse. 



Limnoria andrewsi, sp. n. (PI. V. figs. 7-14.) 



Description of female (not ovigerous). — Length of body 

 when straightened out about 20 mm. ; breadth "65 mm. 



General form of body (fig. 7) narrower than in L. lignorum 

 or L. pfefferi. The first free thoracic somite has only a 

 shallow transverse depression dorsally. The fifth abdominal 

 somite is almost as long, in the middle line, as the telsonic 

 segment ; the latter has a slight median elevation, indistinctly 

 bilobed, anteriorly, and its posterior margin is less evenly 

 rounded than in L. lignorum and L. pfefferi. The whole 

 dorsal surface is beset with short seta?. 



The antennules (fig. 8) have the second segment nearly 

 twice as long as broad and longer than the third. A minute 

 nodule (marked * in figure) bearing two setaa on the distal 

 end of the third segment may perhaps represent a vestige of 

 the accessory (inner) flagellum. In the antenna? (fig. 9) the 

 last segment of the peduncle is nearly twice as long as the 

 preceding. 



The palp of the mandible (fig. 10) is more slender than in 

 any of the described species ; the second segment about one- 

 third longer than the first and nearly three times as long as 

 the third. 



The epipod of the maxilliped (fig. 11) extends as far as 

 the distal end of the ischium ; it is about three times as long 

 as wide, with a bluntly pointed apex. 



The first gnathopod (fig. 12) resembles that of L. lig- 



