NEREIDIFORMIA 



319 



which may be further strengthened by the addition of grains of 

 sand, small pebbles, etc. ; the tubes may be branched. 



Eunice has five tentacles, two great palps, and a pair of 

 nuchal cirri ; the gills are pectinate, and there are four anal 

 cirri. E. Jiarassii And. and Edw. is about 8 inches long. 

 It is reddish-brown, with white spots down the back, one to each 

 segment, and others at the sides. The gills begin at the sixth 

 segment, and when fully developed have eleven branches. The 

 dorsal cirrus is not longer than the gill. E. philocorcdlia Buch. 1 

 forms its tube amongst the branches of 

 Lopliohdia prolifcra, in 200 fathoms, off 

 the west coast of Ireland. 



Marphysa resembles Eunice, but has 

 no nuchal cirri. M. sanguinea Mont, is 

 a fine bronze colour, with bright red 

 gills, which commence on the twentieth 

 segment, and have only four or five 

 branches. The worm, which measures 

 12 to 18 inches, and is as thick as 

 one's finger, hides in clefts in rocks and 

 under stones below low water. Medi- 

 terranean. It is known as " Rock- 

 worm " in the Channel Islands. 



Hyalinoecia, Mgrn., in addition to 

 the five prostomial tentacles and palps, 

 possesses a pair of small " frontal palps " 

 arising from the anterior border of the 

 prostomium ; there are no nuchal cirri, 

 and the gills are simple filiform pro- 

 cesses. H. tubicola Miill., about 3 inches 

 long, is yellowish -brown, and forms 

 a transparent, parchment - like tube. 

 Atlantic and Mediterranean. 



Onuphis Oerst. has a head like the FIG. 170^ Ophryotrocha puer- 

 preceding, from which it differs in having 

 pectinated gills and two nuchal cirri like 

 Eunice. In making its tube it employs 

 small pebbles, bits of shell, and even echinid spines, which it 

 glues together with mucus, so that it bears a general resemblance 

 1 Buchanan, Set. Proc. R. Dublin Soc. viii. (n.s. 1893, p. 169. 



Clap., Metsch. "x 25. 

 ci, Bauds of cilia ; cp, cili- 

 ated pit (uuchal organ) ; J, 

 jaws. (From Korsehelt.) 



