292 



ME. R. I. POCOCK 0~N THE 



Colour for the most part dark reddish brown above, paler 

 beneath ; keels, antennae, and legs testaceous. In young specimens 

 the prevailing colour is a light reddish brown, the central portion 

 of each dorsal plate being scarcely darker than the keels and legs. 

 One adult female also presents this peculiarity of coloration. 



Keels and keel-bearing portion of each dorsal plate densely 

 and finely granular, with a row of larger granules at the posterior 

 margin. Posterior dorsal plates marked indistinctly with three 

 transverse rows of tubercles. Anterior dorsal plates more 

 coarsely granular than the posterior. 



External margin of each keel very obscurely denticulated, and, 

 at the hinder end of the body, produced posteriorly into a short 

 sharp process. In the young specimens, i. e. those possessing 

 but 19 somites and of which the males are without copulatory 

 feet, the granules are relatively coarser and the lateral denticles 

 of the keels much more strongly marked than in the adults. In 

 the largest individual of the series of adults, which is unfortu- 

 nately a female, the lateral margins of the keels are smooth. 



Each somite provided with three tubercles on the outside and 

 two on the inside of the point of articulation of the legs. 



Legs and antenna) thickly clothed with short hairs. Eirst 

 dorsal plate nearly double as wide as it is long ; anterior and 

 posterior margin bearing a single row of tubercles. Each anal 

 valve with a single tubercle ; subanal plate with a tubercle on 

 each side of the middle line. In the male the copulatory foot is 

 composed of two subequal segments ; in the proximal segment 

 the proximal half is slender and simple, the distal half stout; in 

 the distal segment the proximal half is stout, the distal half 

 slender and terminating in two long, approximately equal, hook- 

 like processes. 



This species is allied to Stcnonia marg aritif era (Gervais, Ins. 

 Apt. iv. p. 102), and to Stcnonia Sclietclyi (Karsch, Archiv. 

 Naturg. 1881, p. 37), but differs from both in the shape of the 

 copulatory foot. This organ is in St. Schetchji terminated by a 

 single long curved process; in St, marg aritif era by two curved 

 processes, one long and one short ; and in St. pilipes by two 

 long curved processes. 



BlereD adult specimens (three males and eight females) and 

 four young specimens (two males and two females) were brought 

 from Sullivan Island, King Island, and Owen Island. 



My thanks are due to J)r. Karsch for the name; of this species. 



It is perhaps worth while to point out in connection with this 



