SABELLA. 261 



4. S. bombyx, body short, of a uniform reddish-brown, with a series 

 of black spots on each side above the bases of the feet ; branchiae 

 in two equal brown-spotted tufts circular in expansion, the filaments 

 furnished on the outer side of their rachis with papillary clubbed 

 appendages in pairs at regular intervals ; two setaceous tentacula ; 

 thorax with five setigerous pairs of feet. Length 2-3" ; breadth 

 2-3'". — Tube of fine mud, flaccid, cylindrical, horizontal. Length 

 2-3". 



A Sabella resembling the Penicillus, Mont. Test. Brit. 544. 

 Amphitrite bombyx, Dalyell (1840); and in Pow. Creat. ii. 236. 



pi. 31. f. 1-7 ; pi. 32. f. 1-13 ; & pi. 33. 

 Sabella carnea, Johnston in Ann. Sf Mag. Nat. Hist. xvi. 449 (1846). 



Hab. The coralline region. 



Obs. The body is depressed, and very little tapered backwards, of 

 a uniform reddish-brown, paler on the ventral surface, with about 

 seventy narrow smooth segments. The branchiae are exceedingly 

 pretty, and about one-third the length of the body. The collar 

 under the head is pale and everted. The medio-dorsal line begins 

 on the second abdominal segment, and is continued to the vent. The 

 bristles oifer no specific peculiarity. Sir J. G. Dalyell says, — 

 " This animal dwells in a tube surpassing its own length, which is 

 not of mechanical construction, but is formed by a spontaneous exu- 

 dation from its whole body, comprehending the extremities, or from 

 any part of it. When originally produced, it is clear as crystal, 

 completely exposing the tenant's external organization, of correspond- 

 ing figure. If deprived of the surrounding element, its aspect is 

 somewhat gelatinous, but it seems truly of silken fabric, and becomes 

 quite opake with age. The upper part is corrugated, darker, thicker, 

 and stronger than the rest, evidently for protection of the plume, 

 which is the most delicate part of the creature. The lower extremity 

 is close and obtuse." 



(a) Berwick Bay, Dr. Johnston. 



(b) Aberystwith, J. Henslow. 



5. S. Savignii, body short, of a very pale brown, with a series of 

 dark spots above the bases of the abdominal feet ; branchiae in two 

 equal tufts circular in expansion, the filaments unspotted, smooth 

 on the rachis, ciliated throughout ; thorax with eight pairs of se- 

 tigerous feet. Length 2-3" ; breadth 3"'. — Tube cylindrical, flac- 

 cid, coated with fine mud, even. 



Sabella penicillus, Savign. Syst. Annel. 78. 

 Hab. The coralline region. 



Obs. Of the size of <S. bombyx, but the branchiae are larger, 

 being about one-half the length of the body. They are unspotted 

 and unfasciated in the preserved specimens. The rachis of the fila- 

 ments is very beautifully annulated with the circular dissepiments. 



