Species of the Isopod Genus Serolis. 



303 



defined ; the arched outer margin of this side-plate is minutely 

 serrated, and, like the margins of the succeeding coxal plates, 

 is fringed with long setse. 



The telsonic segment (text-fig. 2) is rather broader and its 

 lateral margins more sinuous than in S. latifrons. The 

 median keel, with a marked pit near its anterior end where it 

 unites with a short curved transverse ridge, is similar in the 

 two species. The submarginal ridge on each side also runs 

 a similar course in both, parallel to the front margin ante- 

 riorly, then curving round to run parallel to the lateral 

 margin, but it is more sharply defined in the new species, and, 



Fig. 2. 



CL 



Serolis beddardi, sp. n., female. Posterior part of body, further enlarged. 

 a, vestige of tergum of eighth thoracic somite ; b, coxal plate of 

 same somite ; c, tergum of first abdominal somite. 



in the anterior part of its course, it is undercut posteriorly 

 On either side of the median keel, behind the middle of the 

 segment, is a pair of short, somewhat irregular, submedian 

 ridges, converging posteriorly. Between the ridges the 

 surface is studded with prominent widely-spaced tubercles or 

 granules. 



The appendages differ very little from those of S. latifrons. 

 The distal segments of the walking-legs are rather less 

 slender. 



Although there is some variation in the relative length of 



