MUSEUM OF COMPAKATIVE ZOOLOGY. 273 



far the greatest number of localities ; they range from the littoral dis- 

 trict to the greatest depths at which Chtetopods have been found by 

 this expedition (955 fathoms, Station No. 29). They are represented 

 by the greatest number of genera (Diopatra, Onuphis, Eunice, Mar- 

 physa, Lisidice, Lumbriconereis, Arabella),' and judging from the large 

 number of their tubes found in many localities, they must form an 

 essential part of the fauna. It is, however, easily seen that the various 

 genera of this family show differences in their vertical 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 floridaua (Pourt.), judging from the occur- 

 rence in great numbers of its paper-like irregular tubes, is a character- 

 istic inhabitant of the littoral belt (as far as 100 fathoms). From deeper 

 waters come the tubes of the Eunice tibiana (Pourt.) ; they descend (in 

 the collection as far as 243 fathoms) about to the region where the Euni- 

 cidea of the species Diopatra and Onuphis appear, some of which build 

 tubes which ai'e frequently very peculiar.* Among these Chaetopods 

 species now appear which perhaps belong exclusively to the deep sea, 

 and which, on account of the large leaflike expansions of the anterior 

 appendages, and the presence of very long hooklike curved bristles at 

 the point, may well be separated from Diopatra as a new genus. I have 

 already pointed out the appearance in the deep sea of such Diopatra-like 

 forms, with the anterior appendages considerably expanded.t The Dio- 

 patra group appears in this collection at about the hundred-fathom 

 line ; the group becomes particularly numerous at Station Xo. 44 at a 

 depth of 537 fathoms, and has one representative at a depth of 955 

 fathoms. 



In connection with the important part here taken by the Eunicidse in 

 the faunal combination of a marine area, it is interesting to remark that 

 among the Annelids found in the lithogi-aphic shales of Bavaria the 

 Eunicidse are just those which, in various forms, are most richly rep- 

 resented. :}: 



Among the other families found at great depths, the Polynoidfc, 

 with the Aphroditidae, may be especially mentioned. But as they are 

 never found in communities, and do not, as a rule, build large tubes, 



* Here belong the flat, parchment-like tubes with cemented sponge spicules, and others 

 mentioned by Pourtales (Bulletin of the Mus. of Comp. Zool., Vol. I. p. 109) of Diopatra 

 Pourtalesii, n. sp. 



+ Zeitschrift fiir Wiss. Zoolofrie, Bd. 2.5, p. 52. 



t Cfr. Palieontographica, XVII. p. 145. 



