SABKLLA. 253 



Confined in a glass of sea-water, it sickens in a few days ; and if not 

 changed, evacuates its tube and dies. 



" In its native abode it recedes on the least alarm ; and when the 

 gelatinous case is taken in the hand, and the animal is extended 

 within it, the sudden contraction within the tremulous tube produces 

 a singular and instantaneous vibrative shock to the parts in contact, 

 that, being unexpected, creates surprise. 



" The essential character of this species is the connected fibres of 

 the tentacula, in which it differs from all others hitherto described." 

 — Montagu. 



I have given Montagu's description entire, for the examination of 

 dead and macerated specimens of so remarkable a worm is not satisfac- 

 tory. It is the type of a distinct genus, or perhaps family. I could 

 not satisfy myself as to the fact, but I believe there is a linear series of 

 uncini on both the dorsal and ventral sides of the small setigerous feet, 

 and that they are all alike constructed. Tiie uncinated lines are not 

 raised above the surface, as are scarcely the setigerous mammillae ; 

 and the tuft of bristles is so inconspicuous that a hand-glass is 

 required to discover their position. The segments are very distinct, 

 but the sutures so much on their level, that the surface is even ; and 

 the difference between the dorsal and ventral surfaces can scarcely be 

 detected. The points of the branchial rays are free, naked, and 

 setaceous. The fans have a tendency to assume a spiral, and they 

 are about a sixth of the body's length. The first segment is apodous, 

 pointed in front on the dorso-medial line, four-lobed, and without a 

 frill. In one specimen of moderate size I reckoned about 120 seg- 

 ments, which I mention to show the worthlessness of such a cha- 

 racter. There is a deep furrow on the anterior part of the ventral 

 surface, which is not continued down the venter, but turns aside and 

 terminates abruptly. 



{a) Kingsbridge Estuary, South Devon, Mus. Leach. 



(Jj) Kingsbridge Estuary, J. Cranch. 



(c) South coast of Devon, Salcombe, Mus. Leach. 



(d) No locahty. 



The Sabella vilJosa of Cuvier (Bcyn. Anim. iii. , and Griffith's 

 Transl. xiii. 12) may be a member of this genus. 



44. SABELLA. 



Sabella, Savign. Sijst. Annel. ^(i. Cuv. Regit. Anim. iii. 191 . Schweigg. 



Handb. 599. Grube, Fam. Annel. 88. 

 Ampliitrite, Lam. Anim. s. Vert. v. 354. Blainville in Diet, des Sc. nat. 



Ivii. 433. 



Char. Body vermiform, distinctly annulated : head defined by a 

 four-lobed everted cartilaginous collar ; the front flat and truncate, 

 bearing a pair of large fan-shaped branchiae, composed of many 

 frino-ed parallel filaments, united on a cartilaginous base : mouth 



