47 132 Proceedings of the Royal Irish Academy. 



Arniandia flagellifera sp. n. 

 PL XIV, figs. 31 a-d. 



A single specimen of this new species was taken in the tow-net near the 

 entrance to Ballynakill Harhour. A well-preserved specimen has also heen 

 dredged in 1 1 fathoms in Galway Bar ; and as the latter individual is in some 

 respects iu better condition than tbe former, it has been largely used in 

 drawing up the following description. 



The body is 12 mm. long in one specimen, and 9 mm. in the other, the 

 latter being more strongly contracted and thicker than the former. It is of 

 very uniform thickness throughout the greater part of its length, tapering to 

 the pointed head, and more abruptly towards the tail. Starting immediately 

 behind the mouth, a ventral groove runs along the body to the anal funnel. 

 It is shallow in front, but gradually deepens towards the middle of the body; 

 and it is bounded laterally by two conspicuously rounded ridges. The colour 

 is pale-brown with a greenish sheen, and any pattern which may have been 

 present in the living worms has vanished. 



There are 33 setigerous segments in both specimens. Each segment is 

 composed of three distinct rings, and each ring is biannulate. The annulation 

 is not very distinct near the ends of the body. 



The head (fig. 31 a) tapers gradually to a slender tip. Xo eyes are visible 

 on the head. 



Iu front of the first setigerous lobe on each side is a conspicuous nuchal 

 organ. 



Loug slender dorsal cirri are present on all setigerous segments except the 

 iu-st and the two last. Their absence from these segments is probably due 

 to accident. 



The lateral eyes occur on 16 setigerous segments, the 4th to the 19th. 

 The posterior ones are small and inconspicuous. In the specimen from. 

 Galway Bay the eye consists of small spheres of pigment, like a compound 

 eye ; but in the Ballynakill specimen the pigment in each eye is fused into a 

 single sphere. 



The anal funnel (tig. 31c is formed of a delicate membrane, ringed 

 externally. The opening is dorsal, sloping from below upwards and forwards. 

 The membrane on each side of the opening projects in four lobes, each lobe 

 bearing a fusiform papilla. 



On the ventral side of the anal funnel, in the median line iu front, rises a 

 long slender cirrus, nearly twice as long as the anal funnel. Such a cirrus 

 has been found previously in two species of Arniandia, A. leptocirris Grubc. 



