PECTINARIA. 243 



organs from one side, on the whole resembhng four combs with long 

 flexile teeth. These branchiae testify considerable action. Colour 

 of the animal reddish. Only one specimen occurred, which had 

 quitted its dwelling ; nor did it construct a new one when supplied 

 with sand and earthy matters." — Dalyell. 



B. Amphictenea. Front armed with a transverse row of stiff bristles. 

 41. PECTINARIA*. 



Amphitritet, Mull. Zool. Dan. i. 27 (1788). Cuvier, Tab. Elem. 1804. 

 Terebellum, Denys de Montfort, Conchiol. Syst. ii. 11 (1808). 

 Cistena, Leach in Suppl. Encyclop. Brit. i. 452. 

 Pectinaria, Lam. Anim. s. Vert. v. 348. Blainville in Diet, des Sc. 



nat. Ivii. 436. 

 Amphictene, Savigny, Syst. Annel. 69 & 88 (1820). 



Char. Body conical, short, appendiculated behind, polypodous : 

 head undefined, the front disciform and obliquely truncate, armed 

 with a row of prominent bristles in two fan-shaped sets above the 

 mouth, which is subcentral, bilabiate, and overhung above by a mar- 

 ginal fringe of numerous short tortuous channeled tentacula : tenta- 

 cular cirri four, a pair on the sides of the first and second segments : 

 branchise in two pairs, on the sides of the third and fourth segments, 

 short, flattened, formed of a closely compacted unilateral series of 

 vascular lamellae. Thoracic portion greatly developed, of seventeen 

 segments, distinguished by a series of setigerous feet along each side ; 

 the foot (excepting the first three pairs) bilobed, the superior lobe 

 with a fascicle of setaceous bristles, the inferior linear-elliptical, with 

 a linear series of minute booklets : abdominal portion separated by a 

 deep stricture, small and indistinctly segmented, apodous. — Tube 

 free, conical, widely open at both ends, composed of agglutinated 

 grains of sand, and even on the surface. 



1 . P. belgica, front obliquely truncate, the space behind the spines 

 smooth ; tentacular cirri simple ; abdomen oblong, truncate on the 

 lower margin. — Tube straight. 



Nereis cylindraria belgica, Pallas, Misc. Zool. 122. pi. 9. f. 3-13. 

 Sabella tiibiformis, Pean. Brit. Zool. iv. 148. tab. 92. f. 163 ; and edit. 



1812, iv. 372. pi. 95. f. 2. 

 Nereis conchilega, Penn. Brit. Zool. iv. 47 (1777)- 

 Sabella belgica, Turt. Gmel. iv. 611. Dalyell, Pow. Great, ii. 178. 



pi. 25. f. 5-9. 



* From pecten, a comb, and suggested by the pectinated form in which the 

 bristles on the head are arranged. 



t When Miiller proposed the genus Amphitrite (1771), it was ill-defined and 

 miscellaneous, but in the Zool. Danica the name is expressly assigned to the 

 species of the Pectinaria of Lamarck. 



R 2 



