188 " ENDEAVOUR " SCIENTIFIC RESULTS. 



twenty -second segment, above which is the " excurrent 

 aperture " noted by Thomson as being formed by excava- 

 tions on the mesial margins of the last pair of elytra, which 

 margins are slightly upturned to limit a definite aperture. 



(6.) The large tufts of very fine dorsal chsetse are so arranged 

 as to meet the neighbouring tufts, before and behind, 

 and these chaetae are covered with numerous fine hairs or 

 long denticulations in which the fine particles become en- 

 tangled as they are being carried inwards by the current. 

 They serve, in fact, as a filtering apparatus. 



(7.) Again, around the base of the dorsal cirrus, in all the 

 species, is a large gland from which the cylindrical cirrophore 

 arises, and thus divides the gland into two portions. 1 This 

 gland is separated from the dorsal cushion by a distinct space 

 on which in some species are the dorsal gill*. May it be that 

 this gland secretes a mucous material which also entangles 

 fine particles which have escaped the filtering action of the 

 cheetse? One finds delicate strands of stuff, with entangled 

 particles, in between the feet and between the cushions. 



The genus is in one respect at least more nearly related to 

 the Aphroditinse than to the Polynoinse, namely in the form 

 of the intestinal caeca, which are long and branched, and the 

 ends reflexed, and lying below the " cushion " and elytro- 

 phores, whereas in the Polynoinse these organs are shorter, 

 simpler, and apparently not bent backwards. 



The genus is, then, a specialised Polynoid in which certain 

 modifications have occurred in the feet as well as in other 

 parts of the body in the direction of perfecting the respiratory 

 functions ; and it presents an interesting instance of adap- 

 tation to its mode of life. 



All the species come from some depth. The New Zealand 

 forms are usually found in from 20-40 fathoms of water, with 

 a bottom of ooze or fine sand. Lt is true that we sometimes 

 find the animal on shore, but it may be that it has been 

 carried there aiter a storm, for they are only occasionally 

 found when shore-collecting. f have found them inside 

 fishes. 



The two Japanese species were obtained from 30-63 

 fathoms ; and the new species occur in deep water, down to 

 200 fathoms. 



1 . A similar gland occurs in other Polynoid genera. 



