POLYCH^TA. — BENHAM. 191 



cirriferous segments). There may also be a couple of small 

 papulae springing from the posterior face of the cushion. A 

 lower row of two, the proximal near the axilla, the distal 

 about half-way down the side of the foot. This row is nearly 

 vertical, running down the axillary angle between the two 

 feet (PI. xxxviii., fig. 22). 



The arrangement on the elytriferous segments is nearly 

 the same, though there are usually three papulae in the lower 

 row on the posterior face, the proximal or uppermost being 

 close to the axilla. 



The parapodium has the form represented by Thomson's 

 figure and illustrated here on PI. xxxix., fig. 38 — it possesses 

 two bundles of chsetae ; the notopodial bundle consists of a 

 very large number of closely set, very fine, almost silky and 

 very flexible bristles, which project as a pencil or brush, 

 spreading outwards in all directions, and touching those of 

 the neighbouring feet (PI. xxxix., fig. 25). Under the micro- 

 scope they are seen to bear a double series of very fine and 

 rather long " cilia " or short hairs, which are covered with 

 fine particles of mud, and evidently act as a sieve. 



The neuropodial chaetae are stout and brown, about 30 in 

 number, arranged in 10-12 tiers of 2-3 in a tier. They differ 

 remarkably from the normal Polynoid chaetae, and resemble 

 those figured by Moore for P. cJdtoniformis. 



The usual " pectinated frills " (of A. G. Bourne) are re- 

 placed by transverse rows of very long, very fine hairs, which 

 spread out on each side. It is impossible, I find, to count 

 the rows, as they successively overlap, but there are at least 

 12-15 or perhaps more (PI. xxxix., figs. 23, 24). 



The aciculum of the neuropodium pierces the foot near its 

 upper margin, and there is here above it a short tongue- 

 shaped lip. There are only about five or six chaetae above the 

 aciculum. 



The dorsal cirrus arises from a swollen base, which appears 

 to be a gland ; it is more largely developed behind than in 

 front of the base. The usual cirrophore and style are 

 distinguishable in the cirrus, which presents no structural 

 characteristic. 



The cirrus is slender in proportion to the size of the animal. 

 The head agrees in general with that figured by Thomson 

 for P. squamosus. 



The prostomium (PI. xxxviii., fig. 16) is about as broad 

 as its length, widest behind the middle, and limited anteriorly 



