HERMELLIFORMIA. 



491 



of each gill-filament ; Protulides Webst. ; Dasychone Sars, gill -filaments with 

 dorsal appendices, D. bombyx Dal., with compound eyes at the base of the dorsal 

 appendices of the gills ; Laonome Mgr. ; Notaulax Tauber ; Sabellastarte Kr. : 

 Eurato St. Jos. ; Haplobranchus A. G. Bourne, estuarine ; Manayunkia Leidy, 

 fresh- water ; Cadbangia Giard, fresh-water, anus ventral and anterior ; Fdbricia, 

 Blv. ; Othonia Johnst. ; Amphicora Ehr., with two eyes on the last segment; 

 Oria Qtf. ; Jasmineira Lang ; Myxicola Koch (Eriographis Gr. ; Arippasa Johnst), 

 gill-filaments connected by a membrane which reaches nearly to their tips ; 

 Chone Kroyer ; Euchone Mgr. ; Dialychone Clp. 



Fam. 2. Serpulidae.* Tube formed of mucine indurated with calcareous 

 matter. Almost always with thoracic membrane and operculum. Without a 

 ciliated groove, but the ventral surface (and sometimes the dorsal) is in part 

 ciliated. The thoracic membrane is formed by the fusion of the dorsal and 

 ventral cirri of the thoracic segments. The operculum consist of a terminal 

 dilatation of one of the branchial filaments. Serpula L. ; sub-genera Hydroides 

 Gunn. (Eupomatus Phil.; Eucarphus Morch.; Polyphragma Qtf.), and Crucigera 

 Benedict. ; Protis Ehl. ; Chitinopoma Lev. ; Filograna Oken, two or several oper- 

 cula ; Salmacina Clp., no operculum ; Spirorbis Daudin (Fig. 400), operculum 

 grooved on one side, serving as 

 brood pouch ; Pileolaria Clp. ; 

 Janua St. Joseph ; Ompha- 

 lopoma Morch ; Circeis, Ompha- 

 lopomopsis, Janita, Leodora, 

 Mera, Hyalopomatopsis, all St. 

 Jos. ; Vermilia, Lmk., etc. ; 

 Pomatoceros Phil. ; Spiro- 

 branchus Blv. ; Pomatostegus 

 Schm.; Placostegus Phil.; 

 Protu la Risso ; (Psygmobranchus 

 Phil. ), no operculum ; Apomatus 

 Phil. 



Sub-order 2. 

 HERMELLIFORMIA. 



The peristomium is 

 enormously developed, and 

 forms a bilobed hood 

 capable of closing over the 

 mouth; the truncated free 

 end of each lobe carries 

 three semicircles of peculiar 

 setae, which act as a protec- 

 tion when the worm is 

 withdrawn into its tube. 

 The prestomium is small, 

 but possesses a pair of well- 



FIG. 400. Spirorbis laevis (after Claparede). a, the 

 animal removed from its tube, strongly magnified ; 

 b, its tube. T tentacles; Bs brood pouch, with 

 operculum ; Dr glands ; Ov ova ; Oe oesophagus ; 

 M stomach ; D intestine. 



* St. Joseph, Ann. ScL Nat. (7), 17, p. 259. 



