12 CLASS ANNELIDA. , 



The Mediterranean possesses a fine and large species, 

 with a calcareous tube, like that of the Serpul®, with orange 

 gills, &c. Sahella protuLa, Nob., or Protula Rudolphii 

 Risso *. 



In others, there is no membranous disc in front; their 

 branchial combs form two equal spirals f. 



There are sometimes two ranges of filaments on each comb J. 



In others again, one of the two combs only is thus formed ; 

 the other, which is smaller, envelopes the base of the first, 

 Sahella unispira, Cuv. ; Spij-ographis Spallanzanii. Viviani. 

 Phosph. Mar. pi. IV. and V. § 



There are some whose gills only form round the mouth a 

 simple funnel, but with numerous filaments, crowded, and 

 strongly ciliated on the internal surface. Their hairy feet 

 are almost imperceptible ; Sahella villosa, Cuv. New species. 



Some, in fine, have been described, which have but six 

 filaments, arranged like a star. Tuhularia Fahricia, Gm. 

 Fabr. Groeul. p. 450 ; it is the genus Fahricia, of Blainville. 



Terebella, Cuv., 



Inhabit, like most of the Sabellse, a factitious tube ; but it is 

 composed of grains of sand and fragments of shells. More- 



* The existence of this magnificent species, and the calcareous nature of 

 its tube, are incontestible, notwithstanding the doubt expressed. Diet, 

 des Sc. nat. hai. p. 432, note. The Sabella hispiralis (Amphritrite volu- 

 tacornis, Trans. Linn. VII. vii.) diflfers very little from it. I dare not 

 affirm that it is the same as Seb. I. xxLx. 1. erroneously cited by Gmelin 

 and Pallas, under Serpula gigantea, for this figure exhibits no disc. 



f These are the simple Sabellae of Savigny. Amphitrite reniformis. 

 Mull. Ven. xiv. or Tubularia penicilhcs, id. ZooL Lxxxix. 1. 2. or Terebella 

 reniformis, Gm. ; Amphitrite infundibulum, Montag., Lin. Trans., IX. viii. ; 

 Amph. vesiculosa, id. ib. XL v. 



X These are the Sabellce Astartce, Sav., such as Sabella grandis, Cuv., or 

 Indica, Sav. ; Tubularia magnifica, Shaw, Linn., Trans. V. ix. 



§ These are the Sabella Spirographicce of Savigny. 



