POLYCILETA-BENHAM. 77 



I cannot trace any other organs. 



The species is manifestly different from S. parvum Ehlers, in which the papillae 

 are fewer, are definitely spaced segmentally in alternating rings of larger and smaller 

 sizes. It differs from S. minutum Webster and Benedict, which is densely clothed in 

 papillae, but they are of two distinct sizes (larger in the parapodial levels, and two or more 

 irregular rows of smaller ones between) ; (see Southern*). Both these species also have 

 definite tentacles. It may be that in specimens of the new species that have not been 

 flattened they may also be found. However, the parapods and the chsetse are 

 dissimilar. 



Family 

 Genus ARICIA Savigny, 



AKICIA MARGIN ATA EMers. 



Ehlers (1897), p. 95, pi. VI, figs. 150-156. 



Willey (1902), p. 275, pi. XLV, fig. 4 (spine). 



Ehlers (1908), p. 116. 



Ehlers (1912), p. 23. 



Nainereis marginata Fauvel (1916), p. 445, pi. VIII, figs. 26-33 (juvenile form). ( 



This species is characterised by the triserial arrangement of the spines in the 

 anterior 13 or 14 neuropods ; by the absence of any fringe or papillae in their neighbour- 

 hood ; and by the gills commencing on the sixth chsetigerous segment. 



The worms before me lack the black lines in the intersegmental furrows and 

 along the margins of the gills, from which the specific name was derived, but it seems 

 now to be recognised that these markings were due to adventitious particles. 



Those from the shallower waters of Boat Harbour are white, are coiled, and have a 

 length of about 26 mm. Some of these contain eggs, so that they are not juveniles. 



One anterior fragment from 318 fathoms is of stouter build and of a pale brown 

 colour, with an iridescent skin. It measures 20 mm., by 3 mm. across the body and 

 2 mm. in height. It consists of a head and only 47 segments. 



The uncini have the form figured by Willey, with a spoon-shaped hollow near the 

 end, below which are transverse ridges. 



Localities. 



Boat Harbour, 2-4 fathoms. 

 Commonwealth Bay, Station 2, 318 fathoms. 



Distribution. South Georgia, Kerguelen, K. Wilhelm-II Land (Ehlers) ; Cape 

 Adare (Willey) ; Roy Cove, Falkland Islands (Fauvel). 



* Southern, Proc. Roy. lrish ( Acad. Set. 1914, p. 90. 



