468 CLASS ECHINODERMATA. 
in some measure, approximates to it, but which may one day 
serve as a type for a new order. It forms a genus which I 
name 
NEMERTES, Cuv. 
It is a worm extremely soft and elongated, smooth, slender, 
flatted, and terminated at one extremity by a blunt point, 
pierced with a hole; widened, and broadly open at the oppo- 
site extremity, by which it fixes itself. Its intestine traverses 
the whole length of the body. Another canal, probably con- 
nected with generation, winds along its parietes, and finishes 
at a tubercle on the margin of the wide aperture. MM. Dor- 
bigny, and de Blainville, who have seen this animal living, 
assure us that the wide aperture is the mouth. 
The only known species, Nemertes Borlasit, Cuv. Borlase. 
Cornw. xxvi. 13., is more than four feet long. It remains 
sunk in the sand, and, it is said, attacks the anomiz, which it 
sucks in their shell. 
Near these nemertes should, probably, be placed 
TUBULARIA, Renieri, 
Equally large, and of a very elongated form; but which have 
a small mouth pierced under the anterior extremity. 
OPHIOCEPHALUS, Quoy et Gaim., 
With the same forms, have the end of the muzzle cleft. 
CEREBRATULA, Renieri, 
Appear to differ only by having a shorter body. 
