New Genus of Terrestrial Isopoda. 13 



Pleon long, of six distinct segments, last joined to telson. 

 Uropoda biramous, short and powerful. Telson large, sharply 

 truncate. 



Phreatoicopsis terricola, n.sp. 



Specific diagnosis. — -Body stout. Pleura of second, third, fourth 

 and fifth segments of pleon moderately developed, being only as 

 deep as their respective segments ; their inferior margins fringed 

 with a few small spinose setae. Telson abruptly truncated. 

 Lower antennae about one-third of the length of the body ; 

 peduncle longer than nagellum ; fourth and fifth joints of 

 peduncle longest and equal in length. Legs long, slender. 

 Lower lip with the adjacent edges of both lobes much hollowed 

 out at the base, so as to leave a wide central space. Inner lobe of 

 first maxilla narrow and with numerous plumose setae at its 

 extremity. 



Colour. — Creamy white. 



Length. — About 45 mm. 



Habitat. — Banks of the Upper Gellibrand Biver, in burrows. 

 (W. H. F. Hill). 



Detailed Description. 



The only specimens that we have hitherto received have all 

 been males, so that the description of the points of difference 

 shown by the female must be deferred for the present. 



Body (Plate III., Fig. 1). — The length of the largest specimen 

 we have is 48 mm. The body is broadest at the third and 

 fourth segments of the pereion and then gradually decreases in 

 width posteriorly. The depth of the body is somewhat less than 

 its breadth in the pereion, but owing to lateral compression is 

 slightly greater than its breadth in the pleon. The differences 

 are, however, not very marked, though, owing to the great 

 downward prolongation of the pleura, the compression appears 

 more considerable than it really is. The dorsal surface of the 

 pereion is very convex, the ventral being only slightly so. In 

 the pleon the dorsal surface is more convex than in the pereion 

 and the ventral surface is flat. 



