CHARACTERISTIC DEEP-SEA TYPES. WORMS. 



55 



Fig. 268. 

 Rhamphobra- 

 chium Agas- 



Of the families here enumerated, none has so important a 

 bearing on the character of the faunal region as that of the 

 Eunicidae. Their representatives are found in far the greatest 

 number of localities ; they range from the littoral district to 

 the lowest depths at which chietopods have been dredged by 

 the " Blake." They are represented by the largest number of 

 genera (Diopatra, Onuphis, Eunice, Rhamphobrachium (Fig. 

 2(58), Marphysa, Lisidice, 

 Lumbriconereis, Arabella), 

 and, judging from the large 

 n umber of their tubes met 

 with in many localities, they 

 must form an essential part 

 of the fauna. It is easily 

 seen, however, that the va- 

 rious genera of this family 

 show differences in their ver- 

 tical range, the bearing of 

 which will perhaps be more 

 clearly understood when the conditions 

 of temperature of their habitat are taken 

 into account in connection with it. Thus 

 the Eunice conglomerans, judging from 

 the abundance of its paper-like irregular 

 tubes (Fig. 269), is a characteristic in- 

 habitant of the littoral belt, as far as 

 100 fathoms. From deeper waters come the tubes of the Eunice 

 tibiana Pourt. ; they descend to 243 fathoms, about to the re- 

 gion where the Eunicidea of the species Diopatra and Onuphis 

 appear, some of which frequently build very peculiar tubes; 

 such as the flat, parchment-like tubes with cemented sponge 

 spicules of Diopatra Pourtalesii, and others mentioned by 

 Pourtales in his preliminary account of the results of his first 

 expedition. 



Among these chaetopods species now appear which perhaps 

 belong exclusively to the deep sea; they are separated from 

 Diopatra-like forms, with large leaf-like expansions of the ante- 

 rior appendages, and with long hook-like curved bristles at the 



Fig. 269. Eunice conglom- 

 erans. %. 



