Clare Island Survey — ArcJiianndida and PolifcJiaeta. 47 9U 



space. From the 15th to the 25th segment they meet in the mid-dorsal 

 line, then further behind they are shorter again. 



In the 15th or 16lh setigerous segment a row of hooks appears in the 

 ventral division oil the feet (fig. 23.)). They have an unusually long main 

 tooth, bent at right angles to the shaft, and crowned with two sharp spines. 

 The shaft is curved distally, and above the curve it is slightly constricted. 

 The wing which envelops the distal end of the seta is wide beneath the 

 main tooth, and then abruptly narrows towards the neck of the seta, and is 

 very characteristic in outline. 



The 24th foot (fig. 23f) does not differ much in outline from the 10th foot. 

 The dorsal division bears long and short setae, all of which are striated. The 

 ventral division has 13-15 crochets, and 2 or 3 slender capillary setae. None 

 of the setae have dotted blades. 



In the posterior feet (fig. 23 g) the lamellae are more conspicuous. The 

 branchia is short and the dorsal lamella projects outwards, forming an angle 

 with the branchia. The ventral lamella is rounded and foliate. The dorsal 

 setae are long and striated. The ventral division has 10-12 crochets, and 

 3 or 4 slender capillary setae. 



The anal segment (fig. 23 b) bears a ventral flattened expansion, which is 

 more or less bilobed. This structure seems to be intermediate between the 

 anal cirri of Spio and the anal funnel of Nerine. 



Mature specimens were found in September. 



This species differs in many respects from Nerinides longirostris (Quatr.). 

 It is much smaller in size, has the four eyes in a transverse row, instead of 

 in a square, and the ventral crochets begin on the 15th segment, whilst those 

 of M. longirostris begin on the 33rd-45th segment. These setae have a very 

 long main tooth crowned with two spines, whilst those of iV. longirostris have 

 a medium tooth with a single spine. The lamellae on the feet are more 

 prominent in the posterior part of the body of the present species than those 

 of N. longirostris, and the anal segment is cpiite different. JV. longirostris 

 lives in clean sand, N. tridentata in Laminaria roots. 



Habitat. — Blacksod Bay. Found on 5 occasions, in Laminaria roots from 

 near low-water mark. 



Nerine cirratulus (Dellc Chiaje). 

 1896. Nerine cirratulus. Mesnil, p. 152. 



In the sandy beach at the head of Feorinyeeo Bay, in Blacksod Bay, 

 there is a zone of sand, two or three feet below high-water mark, where this 

 species occurs in immense numbers. The sand is quite honeycombed with 

 their burrows, and is stained with their secretions. In other parts of the 



N2 



