336 MR. F. E. BEDDARD ON THE ISOPODA COLLECTED [May 20, 



furnished with a median, backwardly projecting spine ; these spines 

 are considerably larger in the female than they are in the male ; the 

 rest of the body is perfectly smooth and free from tubercles. The 

 epimera are short and closely approximated, the points only of the 

 fourth, fifth, and sixth projecting freely ; the suture separating the 

 fifth thoracic segment from the first abdominal is continuous from 

 one side of the body to the other; the dorsal portion of the sixth 

 segment is not represented as in the other Australian forms. The 

 cephalic shield is almost triangular in outline from the great develop- 

 ment of the ocular prominences and the posterior spine. 



The caudal shield is hexagonal in outline, the posterior end 

 markedly bifid ; it has a longitudinal keel, and on either side, just 

 below and to the inside of the notch which covers the articulation 

 of the last pair of appendages, is a minute flattened tubercle. The 

 abdominal segments have a median ventral spine, larger in the female. 



The second pair of antennae are slightly longer than the first 

 pair; the fifth joint is remarkably large and swollen, and this feature 

 serves to identify the species. 



The lower surface of the labium and basal portion of the mandibles 

 and maxillipedes is much sculptured. 



Station 163a, 35 fathoms; and Station 162, 38-40 fathoms. 



8. Serolis longicaudata, n. sp. 



The aspect of this species is peculiar and very unlike the typical 

 form of the genus. The anterior portion of the body is almost com- 

 pletely circular, and the caudal shield is extraordinarily long, about 

 half as long as the rest of the body ; the epimera are short and trun- 

 cate at their outer ends. The segments gradually increase in breadth 

 up to the fourth ; the fifth and sixth are considerably shorter. The 

 suture between the epimera and the tergal portion of segments two 

 and three is situated about halfway between the articulation of the 

 limb and the outer margin of the segment, and in the succeeding 

 segments comes to approximate more closely to the point at which 

 the limbs arise ; hence the epimera themselves gradually increase in 

 length from the first to the sixth as in all other species, though the 

 circular form of the body makes it appear at first sight as if the third 

 pair were the longest. 



The single specimen contained in the 'Challenger' collection is a 

 female ; it measures 7 millim. in length and 5 millim. in greatest 

 breadth. The surface of the body is quite smooth and free from 

 tubercles ; the sides of the thorax slope gradually downwards from 

 the central portion, which is roof-shaped ; the cephalic shield is not 

 completely separated from the thoracic segment, the suture being 

 incomplete posteriorly for a short space on either side of the median 

 line ; the fifth and sixth thoracic and the first abdominal segments 

 are fused in the middle line. 



The caudal shield is pentagonal in shape and longitudinally carinate ; 

 the last pair of appendages are attached about halfway down the 

 side of the shield, and from this point a faint transverse ridge passes 

 across at right angles to the longitudinal keel ; a curved ridge follows 



