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side of the belly which is flatted ; the sides of the body are 
bristled with a great number of stiff setae, long, thick, espe- 
cially in the middle, of no great lustre, and whitish, forming 
two longitudinal distant ranges, each ring supporting two of 
these setae at each side. A singularity which they present is, 
that they are all turned forwards, contrary to their arrange- 
ment in all the other annelida; the setae of the rings which 
compose the anterior extremity are very large, crowded against 
each other horizontally, so as to imitate on each side a sort of 
comb, directed forwards, as in M. Lamarck’s division of am- 
phitrite (pectinaria ), and furnished at its root with a consi- 
derable quantity of tentacular cirri, extremely short and labial ; 
between these two fasciculi, and at the inferior face, is the 
head, properly so called, of a conical form, adherent to the 
body by the summit of the cone, and elongated anteriorly into 
a small proboscis ; it is at the base of this elongation that the 
first buccal orifice is placed, which is continued in a sort of 
gutter for its whole length, and which M. Otto considers to 
serve as a sucker ; the second mouth is farther back ; it is 
much larger, and surrounded by a labial pad, in the form of a 
horse-shoe, at the posterior part of which is a pair of tenta- 
cula, sub-compressed, mobile, sub-articulate, and with a deep 
furrow on the edge ; the anus is rounded, large, and altogether 
terminal. No other orifice has been observed on the exterior 
of this animal. 
The cutaneous envelope, rather thin, and transparent enough 
to let the nervous and vascular system be seen through it, is 
formed of two laminm, one of which is the skin, properly so 
called, and the other, which M. Otto names the peritoneum, 
still thinner, is very little adherent ; the latter, at the anterior 
third of the body, separates the anterior cavity into two very 
unequal parts, by a sort of diaphragm, pierced only by the in- 
testine ; it is in the anterior part that lie the principal viscera. 
The two mouths have each an oesophagus, about an inch long, 
