of Gastrotrichous Rotatoria. PAW 
little, and appears to contain a small nucleus. These dilata- 
tions appear at first like little spots of the cuticle, and the 
latter consequently appears, under a sufficient magnifying- 
power, to be punctate. 
The dorsal surface of the body is even. On the other hand, 
its ventral surface has some small appendages, of a conical 
form, whose position and number are always the same: all 
show the same conformation; they are cones formed by a 
prolongation of the cuticle, and enclosing an axial cord, which 
can be easily traced to the parenchyma of the body. This 
cord is separated from its cuticular covering by a liquid or 
semiliquid stratum. We find first of all six of these conical 
appendages disposed in a half-ring a little behind the buccal 
extremity ; the two outermost are the largest, and the two 
innermost the smallest; the two intermediate ones have a 
medium size. 
The following appendages are distributed in pairs on the 
two sides of the body, but in such a manner that the first two- 
fifths of its length are destitute of them. Between the two 
hindermost appendages are placed eight others of smaller size, 
in a transverse line. Lastly, there are two more placed near 
the generative pore. In all the cones in the posterior part of 
the body the axis appears to me to be double. 
All these appendages are moveable, and serve, no doubt, as 
tactile organs, perhaps also as levers facilitating locomotion. 
Those which form transverse ranges appear to be mutually 
dependent, and move together like a comb. 
The cuticle also bears vibratile cilia, which appear to play 
the principal part in locomotion when the animal is free : these 
cilia are exclusively ventral; they form a band which extends 
from the foremost pair of conical appendages for almost two- 
fifths of the total length of the animal. At this point, which 
is exactly at the level of the union of the cesophagus and in- 
testine, the ciliated band stops abruptly; behind there are 
no vibratile cilia. The Hemidasyes, therefore, properly speak- 
ing, are Thoracotricha rather than properly Gastrotricha. 
The anterior extremity is separated from the rest of the 
body by a slight constriction at the level of the anterior pair 
of ventral appendages. This part may be designated by the 
name of cephalic lobe, although," leaving the mouth out of con- 
sideration, it presents nothing which could characterize a head. 
This lobe is covered with slender and stiff bristles, like the 
tactile bristles of the Mollusca, Annelides, and Turbellaria, 
and in particular those of the other Gastrotricha. The 
mouth is terminal, surrounded by a circular lip broken up into 
little obtuse papillae and covered with vibratile cilia. It leads 
