324 THE ANNELIDA POLYCHAETA. 



LUMBRINEREIDAE. 



In this family the body is more or less elongate and cyhndrical, ordinarily 

 narrowed anteriorly but more strongly so posteriorly; distinctly segmented. 

 The skin is of tough consistence and is smooth and strongly iridescent. 



The prostomium is most commonly conical, or sometimes more rounded. 

 Both tentacles and palpi are most commonly absent, or three tentacles may be 

 present in the Lysaretinae. Eyes present or absent. 



First two somites without appendages and smooth, or the second sometimes 

 setigerous. Mouth commonly having two hps. 



Parapodia uniramous, well developed. No ventral cirri are present, while 

 the dorsal cirri are either foUaceous in character or rudimentary. Branchiae 

 only rarely present (Ninoe). 



The setae may be of various types. In some all the setae are of a simple, 

 capillary, laminate type, while in other cases crochets, or crochets and composite 

 setae are present. 



The proboscis is armed with a pair of mandibles, or these may be obsolete, 

 and with a definite and commonly, but not always, even number of maxillae. 



Both anterior and posterior regions may be regenerated in some forms at 

 least (Lumbrinereis, Halla). 



The lumbrinereids occur in mud and sand and under stones in the Uttoral 

 zone, as well as down to depths exceeding two thousand fathoms, as in the case 

 of Lumbrinereis ahyssorum secured by the Challenger off the west coast of 

 South America at a depth of 2,225 fathoms. Many have been taken from the 

 stomachs of fish. 



The species of certain genera are normally commensals or parasites during 

 all or the early part of their lives. Lahrostratus parasiticus was found by St. 

 Joseph (Ann. sci. nat., 1888, ser. 8, 5, p. 219, 221) occurring in the general 

 body-cavity of various syllids, such as Odontosyllis ctenosoma, Eusyllis monili- 

 cornis, Pionosyllis lamelligera, Syllis prolifera, and Gruhea clavata. In this species 

 the adults may be free and non-commensal. Oligognathus honelliae Spengel 

 occurs in the body cavity of the gephyrean BoneUia (Spengel, Mitth. Zool. stat. 

 Neapel, 1882, 3, p. 15, pi. 2-4). Haematocleptes terehellidis Wiren seems to live 

 a completely parasitic life in the blood sinus of the wall of the stomach of Tere- 

 bellides stromi (Bih. K. Svenska vet. akad. Handl., 188G, 11, no. 12). This form 

 shows a strong reduction of the maxillary apparatus, an atrophy also evident, 

 but less marked, in Labrostratus. Lahidognothus parasiticus Caullery (Compt. 



