ON ANNELIDA. 87 



gizzard. We also observe in them a vessel filled with red 

 blood, longitudinally directed, and which in the living animal 

 exhibits very marked contractions. 



M. Cuvier originally attached both his Sabella and Tere- 

 bella to this genus. 



The SiPHOSTOM,^ is a very remarkable genus of these 

 animals, established by Dr. Otto, in a dissertation printed at 

 Breslau in 1820, on an animal discovered and observed first 

 on the coast of Naples in 1818, and which he has thus charac- 

 terized : body cylindrical, articulated, elongated, attenuated 

 at the two extremities, enveloped in a skin extremely thin, 

 diaphanous, provided on each side with a double series of 

 setae, directed forwards, and the anterior of which approxi- 

 mated, forms two sorts of advanced combs ; the mouth inferior, 

 subterminal, with a mass of cirri extremely numerous in front, 

 and a pair of tentacular cirri behind, composed of two orifices, 

 placed one before the other, the first smaller, canaliculated at 

 the base, with an advancement in the form of a proboscis, and 

 the second much broader and more rounded behind. How- 

 ever extraordinary may be this character of a double mouth, 

 an arrangement not known in any other animal, M, Otto has 

 described and figured it with so many details, that it would be 

 difficult to deny its existence, however one might be at first 

 disposed to do so. Some doubts, however, may attach to the 

 use of these two orifices, as one of them might very well be 

 supposed to belong to the apparatus of generation. Be that 

 as it may, we shall present our readers with M. Otto's descrip- 

 tion of this curious animal, which he names S. cUjolochaites. 



Its body cylindrical, elongated, flexuous, and about three 

 inches long, is attenuated at the two extremities, but especi- 

 ally behind ; at the distance of about half an inch from the 

 anterior, it presents an enlargement, an indication of the place 

 occupied by the viscera; the number of segments of the body 

 is about forty, but they are not very distinct, except on the 



