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 Siphostojvle 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. diplochaites . 
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 
