FAMILIES, GENERA, AND SPECIES OE THE BRITISH MARINE 



ANNELIDS. 



(ANNELIDA POLYCH^ETA, continued.) 



Family XXVI. — Hermellim: (De Quatrefages), Malmgren, 1867. 



This family has borne various titles, such as Tubularia, Ellis ; Psamatotus, Guettard ; 

 Tubipora, Linnaeus ; Sabella, Linnaeus and Gmelin ; Nereis, Pallas ; Amphitrite, Cuvier 

 and Dumeril ; Ohrysodon, Oken ; Sabellaria, Lamarck, De Blainville, Thompson, Grube ; 

 Amymone, Savigny ; Eermella, Milne Edwards ; Hermelliens, De Quatrefages ; Hermel- 

 laeea, Grube; Sabellariens, De St. Joseph. 



The anterior region (the prostomium being invisible) bears two great lateral lobes 

 homologous with the first pair of feet, which have ventrally prehensile tentacles, and 

 dorsally a crown of opercular bristles from the fused buccal lobe. Only in the remark- 

 able type (Gryptopomahis Geayi, Gravier *) is there a distinct prostomium soldered to the 

 great lateral lobes, and with a median tentacle inserted ventrally. The body is composed 

 of three distinct regions. The buccal segment has a fascicle of bristles on each side; 

 anteriorly is a large folded lamella, hollow inferiorly, with numerous lateral tentacles. 

 Frontal margin provided with a crown of paleae. The posterior (caudal) region is slender, 

 smooth, non-segmented. Feet of the anterior (thoracic) and posterior (abdominal) regions 

 provided with ligulate branchiae. Inferior division of the foot similar throughout and 

 armed with bristles. Dorsally, short, pectiniform hooks occur in transverse rows on 

 lamellae. Tubes in masses (colonial), rigid, composed of coarse sand, or minute pebbles. 



This was the sixteenth family (Sabellariadae) of Dr. Johnston (1865), and he gave 

 the body two regions, with a disciform head having concentric circles of dissimilar and 

 peculiar bristles. Branchiae in pairs on all the segments, dorsal, ligulate and narrow. 

 Feet biramous. 



The body-wall in the anterior region of Sabellaria spinulosa, R. Leuckart (Fig. 136), 

 has externally cuticle and a fairly developed hypodermic layer with basement-tissue 

 and a circular coat internally. Special lateral processes of hypoderm, muscular and 

 other tissues bearing the hooks occur in this region. The coelom is occupied by the 

 large pharynx, which presents a thick wall composed of concentrically arranged circular 

 fibres, the central cavity having a coating of columnar epithelium of considerable thick- 

 ness. The dorsal longitudinal muscles are larger and more massive than the ventral, 

 and form a thick band, while through them at intervals pass muscular fibres, widely 



1 ' Ann. Sc. nat./ 9 e ser., t. ix ; p. 288, pi. vii, 1909. 



170 



