PHYLLODOCIDAE. 97 



long. 81° 31' 9" W.). Depth 1,036 fathoms. Bottom dark brown mud. Bot- 

 tom temp. 37.3° F. 12 November, 1904. One specimen. 



Nepthys sp. 



A fragment of a specimen belonging to this genus was dredged from a 

 depth of 39 fathoms off the Coast of Mexico (Sta. 3418). Expedition, 1891. 

 It lacks both ends. 



Phyllodocidae. 



A large family in which the body, while usually more or less elongate and 

 vermiform and either cylindrical or depressed, varies enormously in size, with 

 the number of somites from comparatively few (e. g. twenty-three) to eight 

 hundred or more. 



The prostomium is of various forms, bluntly subconical to suboval. With 

 four tentacles and often in addition with an unpaired median tentacle normally 

 posterior in position. Palpi none. Eyes two or four, usually small but larger 

 in the epitokous forms, rarely absent (Paralacydonia). 



Tentacular cirri from one to four pairs (or possibly five in Kinbergia) borne 

 on from the first one to the first three somites, or none (Paralacydonia). 



Nuchal organ from strongly developed to none. 



Nephridia with inner end always closed, in connection with numerous 

 solenocytes. The genital funnel distinct though often at maturity opening into 

 the nephridial canal. Aside from the phyllodocoids, the Glyceridae and the 

 Nepthydidae alone present these conditions (see Goodrich, The nephridia of 

 the Polycheta, Quart, journ. micros, sci., 1900, 43, p. 699). 



The parapodia in most cases uniramous with a single aciculum and one 

 fascicle of setae; in other cases biramous and with two acicula. Certain forms 

 in the epitokous phase acquiring natatory simple setae as in the syllids. Neu- 

 rocirri and notocirri flattened, thin and foliaceous, and all containing strongly 

 developed mucus-glands. The cirri in the aberrant Paralacydonia, however, 

 vary from this normal type. 



Setae in most cases composite, but sometimes in part simple and very rarely 

 (Nans) all simple. Certain epitokous forms acquiring special, simple, long, nata- 

 tory setae. 



Pygidium with two anal cirri which are either subulate or foliaceous. 



Proboscis commonly powerful, bipartite, and smooth, or bearing variously 



