56 THREE CRUISES OF THE 



point. The Diopatra (Fig. 270) group begins near the hun- 

 dred-fathom line ; it becomes particularly numerous at about 



Fig-. 270. Diopatra g-lutinatrix. -^. 



500 fathoms, and still has one representative at a depth of nearly 

 1,000 fathoms. 



In connection with the important part here taken by the 

 Eunicidse in the faunal combination of a marine area, it is in- 

 teresting to remark that among the annelids of the lithographic 

 shales of Bavaria the Eunicidse are those which, in various 

 forms, are most richly represented. 



One of the most interesting of the deep-water types collected 



Fig. 271. Buskiella abyssorum. . (Mclntosh.) 



by the " Challenger " is the eminently embryonic Buskiella (Fig. 

 271), which bears the closest resemblance to a chsetopod larva. 



Of other families found in deep water, the Polyuoidse and 

 the Aphroditidse may be especially mentioned. But as they 

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

 tubes, they are, like the Opheliidse, less characteristic of the 

 localities to which they belong than the Maldanidse, or the 

 Ampharetidse ; their large tubes, built of mud, and sometimes 

 associated with those of the Eunicidse, must, judging from 

 the masses in which they are found, be a marked feature of 

 certain localities. 



