430 EUNICE FASCIATA. 



Pruvot and Eacovitza (1896) x distinguish between this form and E. torquata, De 

 Quatrefages. Thus the colour of E. torquata is generally brown, and the sixth segment is 

 always coloured white on the dorsal surface. Median tentacle only as long as the first 

 four segments, whereas in E\ fas data it is as long as eight. All the appendages are 

 moniliform, with brown bars. Branchiae begin on the fifth segment and go to the posterior 

 end, with the exception of the last twenty-five in an example of 140 segments. Maximum 

 divisions of branchiae between seventeenth and thirty-eighth are about ten. Spatulate 

 bristles with a long filament at both edges, whereas in E. fasciata there is only a long 

 filament on one edge. Aciculi black and without valves— whereas those of E. fasciata 

 are brown, with two valves. Dental plates support a third which is the length of the 

 mandibular piece (this refers to the maxillae and the posterior piece). 



Some of these distinctions are doubtful, but certainly the black spines are 

 characteristic. 



Hornel (1891) shows a form which he refers with doubt to E. fasciata, with a 

 maximum of twenty divisions to the branchiae. 



Gravier 2 records E. fasciata as a temporary commensal in Ostrea edulis from 

 Coutances on the shores of France. It does not seem to interfere with the mollusk, the 

 microscopic food of which would not offer much temptation to a form which habitually 

 selects Crustaceans, Annelids, Bryozoa, and Synapta3. Moreover Phyllodoce rubiginosa, 

 Nereis Dumerilii, and Lagisca extenuata were found under the same circumstances, thus 

 probably pointing to accidental commensalism. 



A form dredged off the Hebrides (in the Minch) by Dr. Gwyn Jeffreys in July, 

 1866, shows certain marked differences from E. fasciata, though apparently resembling 

 it. Thus the branchia3 commence on the third foot, speedily increase in the number of 

 filaments, which in those best developed are fifteen, then gradually diminish, and cease at 

 the forty-seventh foot. The absence of branchiae throughout the rest of the body 

 posteriorly thus differs from the condition in E. fasciata. It agrees with E. fasciata in 

 the maximum number of the pinnae of the branchiae, but these go no further than the 

 forty-seventh foot. 



The general form of the dental apparatus is similar, but the great dental plates have 

 seven teeth on the left, and eight on the right, the first on that side being occasionally 

 bifid. The azygos plate has eight teeth; the curved plate in front about the same 

 number, and only one continuation plate with a smooth edge is present beyond the latter 

 (absent on the left from rupture). On the right the anterior curved plate has about 

 twelve teeth, and a single flat plate with a smooth edge continues the curve. 



The appendages to the maxillae form together a spathulate process. The mandibles 

 are similar to those of E. fasciata, with a tooth at the inner third of the anterior edge. 



The foot likewise diverges from that of E. fasciata. At the tenth there are at most 

 ten divisions of the branchiae. The setigerous region is less prominent and the ventral 

 cirrus forms a smooth pad without the terminal process of E. fasciata. The dorsal 

 bristles do not differ much, but the jointed ventral have the first or proximal point of the 

 hook directed straight outward and not distally inclined as in E. fasciata, The edge of 



1 'Arch. Zool. exper./ 3 e ser., t. iii ; pp. 384, 389, et seq. 



2 f Bull. Mus. Hist. Nat. Paris/ vi, p. 415, 1900. 



