408 THE ANNELIDA POLYCHAETA. 



side of the body. The free part of the crochet presents typically a more or less 

 narrowed region, or cervix, distad of which the crochet bears a number of teeth, 

 with a larger one at the angle more or less curved toward the shaft. Ordinarily 

 under the large tooth is a hair, or a group of hans, which embrace or partly cloak 

 it. In the Heteromaldaninae, subfam. nov.,^ the crochets are dorsal and the 

 capillary setae ventral. 



A number of the preanal somites may be achaetous. 



The anus is either terminal or more or less dorsal. There may be a median 

 process of varying development beneath it. Tlip anal somite may be simple 

 or it may be developed into a funnel, which may be entire, toothed, or more or 

 less incised into cirriform processes. 



The alimentary canal is straight. There is a proboscis ordinarily well 

 developed. 



The neplu-idia open near the lowermost crochets, or less commonly near the 

 upper part of the rows. 



Maldanids are easily broken, and specunens with anterior or posterior 

 regenerated ends are frequently met with. 



The maldanids construct tubes which have walls that are often thick and 

 which may be composed of mud, sand, shells of Radiolaria and Foraminifera 

 and similar materials upon a thin, membranous lining, or sometimes the tube 

 without foreign material ocem's in empty mollusc shells, etc. They occur in 

 the crevices of rocks, in mud or muddy sand, etc. They are found, on the one 

 hand, in shallow water, in the beds of Zostera and similar places, and, on the 

 other hand, down to great depths, Sonatsa meridionalis (p. 416), coming from a 

 depth of 2,222 fms, and Nichomache benthaliana having been dredged by the 

 Challenger from 2,300 fms. 



Commensals and parasites on the maldanids are not rare. Thus McCann 

 (Bull, scient. 1888, 19, p. 421) records the copepod Hersilionides pelseeneri 

 Canu {Antheria latericia Grube) as a conunensal in the tubes of Euclymene 

 lumbricoides Quatrefages. Nordmann (Bull. Soc. nat. Moscou, 1864, 37) 

 records another copepod, Donusia clymenicola, as a parasite on a maldanid, 

 Nichomache lumbricalisa; and Levinsen (Viden. meddels., 1878, p. 360, pi. 6, 

 f. 1-4) notes the occurrence of the copepod, Rhodinicola elongata, on the 

 dorsum of Rhodine loveni Malmgren; certam annelidicolous members of 

 Loxosoma also occur on maldanids (Prouho, Compt. rendus Acad, sci., 1890, 

 110, p. 799). 



' For Heteromaldane Ehlers. 



