VENUSIA. 241 



in its sides. The tube follows no regular course, wherever con- 

 structed." — TJulyell. 



39. VENUSIA. 



Char. Body vermiform, with setigerous and uncinated feet to all 

 the segments : head disciform, with an everted cartilaginous border 

 produced on each side of the mouth into a tentacular lobe : mouth 

 inferior, over-vaulted with a cartilaginous concave hood : sternal 

 band continuous down the abdominal surface, and coequal in seg- 

 mentation : branchiae tufted, one pair : bristles and uncini as in 

 Terehella. — Tube adherent throughout, horizontal. 



1 . V. punctata. 



Sabella couchilega, Mont. Test. Brit. 547- 



Terebella conchilega, Dalyell, Pow. Great, ii. 1.99. pi. 28. f. 3-8. 



Hab. The coralline region, very common. 



Obs. The tube is adherent throughout, generally constructed on 

 old bivalve shells ; and the inside of a valve of Venus islandica is an 

 especial favourite locality. It is cylindrical, equally open at both 

 ends, sinuous, from G to 10 inches long, thicker than a quill, coated 

 completely with gravel and fragments of shell ; and occasionally 

 ornamented with pieces of the common Sertularice. 



The worm is of a translucent pale-reddish colour, and smooth. 

 The tentacula are numerous, long and very extensile, prettily speckled 

 with reddish spots. The branchiae are in a single pair, and, unlike 

 those of Terebella, they consist of a tuft of simple filaments tapered 

 to the tip, which is dark-coloured. The body is of the usual form ; 

 the thick anterior portion composed of narrow segments, and gradu- 

 ating into a knotted cylindrical abdominal portion of considerable 

 length. Its segments are at first shorter than their diameter, but 

 they soon become longer, until they at length are twice as long, and 

 thickened at their junctions, making a segment having some resem- 

 blance to a dice-box. These segments are all speckled with scarlet 

 dots. But the peculiar marking of the dorsal surface constitutes the 

 distinguishing character of the species. It is punctated, in a very 

 pretty way, with clear roundish spots, imitating lacework in their 

 arrangement. The character is very obvious with a hand-glass in 

 every specimen I have examined. The sternal band is continued, 

 but the first seventeen segments are most marked, and constitute the 

 thoracic portion. The abdominal is terminated by a caudal portion 

 composed of small short segments, and having the appearance of a 

 regenerated part. The feet are similar on all the segments ; the 

 thoracic placed on a thickened lateral fascia ; the abdominal on the 

 thickened posterior edge of its segments, where they form a very 

 prominent mammillated tubercle on each side. The bristles and 

 uncini present no describable peculiarity. 



