306 Mr. J. W. Piycla on Annelida Polychceta 



It has also been found off S.W. Ireland, North Unst, 

 Shetland, Valentia, in Donegal Bay, and at Plymouth. 

 Examples found in Ceylon and given as O. conchylega hy 

 Dr. Willey are found to resemble tliose at Plymouth, and so 

 should more eorrectly be called O. britannica. No record o£ 

 this annelid is given in 'Challenger' Reports, in Izuka^s 

 'Errantiate Polychaeta of Japan/ nor in Friedrich Eulcn- 

 stein's ' Ueber Onuphiden der Nordsee.' 



The head bears in front two lobate tentacles, which are 

 hardly as long as those of O. conchylega. Behind are situated 

 five long tapering tentacles which arise from ringed cirro- 

 phores. The median, situated on the dorsal mid-line, is the 

 longest and is most posterior in position. In front of it in 

 several si)ecimens is a well-marked black spot. On each side 

 and a little in front of it are two lateral tentacles, of which 

 the inner are the longer, and at the bases of which are the 

 eyes, which are fairly large and black in colour. The palpi, 

 ventral in position and considerably flattened, are separated 

 by a median fissure, which widens as it extends from the 

 base to the tip of the palpi. 



In some of the smaller forms the body resembles that of 

 the Hesionidfe. It tapers anteriorly, but more so posteriorly, 

 and has about forty segments. The peristomial segment, 

 carrying the tentacular cirri which arise from the centre of 

 the segment, is very narrow and has two black specks at the 

 bases of the cirri, which are not ringed and are slender when 

 compared with the tentacles. The black specks continue to 

 the tenth feet, but gradually fade after the commencement 

 of the branchiffi, which continue as single filaments almost 

 to the tip of the tail. The body is rounded dorsally, espe- 

 cially in the anterior region, and flattened ventrally, while a 

 fairly deep median groove runs from head to tail on the 

 ventral surface. When this groove is examined under a 

 microscope the nerve-cord is found beneath it, and near the 

 posterior end of the segment the cord swells out and forms 

 little ganglia. In colour the ventral surface is lighter than 

 the dorsal, and between the ganglia and at the bases of the 

 feet there are whitish patches. The general colour is pale 

 brownish, with an iridescent lustre, but posteriorly this 

 colour is lost owing to the faeces which appear under the 

 thin body-wall as dark green masses. The body ends in 

 two caudal cirri which arise beneath a dilated anus which 

 is present in only a few specimens. 



