218 M. E. Claparéde on a new Genus 
into a cavity which may be regarded as the buccal cavity, and 
from this into a straight muscular cesophagus, which extends 
through the first two-fifths of the body. This part of the diges- 
tive tube alone can enable us to understand the approximation 
that M. Ehlers has attempted to make between the Gastrotricha 
and the Nematoida. However, this analogy is of no import- 
ance. The cuticle of the cesophagus is a little thicker imme- 
diately behind the buccal cavity. The intestine is cylindrical 
and of a yellowish green colour, with its walls filled with 
granulations and little drops; it extends in a straight line to 
the anus. The rectum is colourless. 
The nervous system is unknown in all the Gastrotricha 
hitherto investigated. In Hemidasys agaso this system seems 
also wanting, unless we may regard as of nervous nature four 
pairs of homogeneous and colourless globules lodged in the 
thickness of the parenchyma. Such an interpretation, how- 
ever, would be very hypothetical. We might urge in its favour 
the fact that the first pair of these organs is in relation with a 
pair of little vibratile pits of the surface. These little organs 
remind us involuntarily of the vibratile pits of Nemertes and 
of many other Turbellaria, as well as of those of some An- 
nelides—organs to which sensitive functions have often been 
ascribed. However, even in this case the functions of sensa- 
tion are far from being demonstrated. The idea of an aqui- 
ferous or excretory system also naturally presented itself to 
my mind; but there was nothing to support this in my ob- 
servations. 
Hemidasys agaso is hermaphrodite. Originally I enter- 
tained a diametrically opposite opinion with regard to its 
sexual characters. In fact I had only found individuals with 
well-developed testes; but subsequently I found others loaded 
with their eggs, although otherwise formed like the first, and, 
in particular, furnished, like them, with a testis. If the indi- 
viduals containing zoospermia but without eggs are frequent, 
on the other hand I have never met with individuals provided 
with eggs and destitute of zoospermia. This is how I explain 
this particular form of hermaphroditism :—Each individual 
only produces one egg, or rarely two at a time. After laying 
this egg, and before producing a new one, it loses temporarily 
all the characteristics of the fémale sex ; nevertheless its male 
apparatus continues to possess zoospermia: hence an apparent 
predominance of the male sex. 
The testis is an oval pouch, situated close to the intestine in 
the posterior part of the body. I have always found it filled 
with groups of zoospermia, fascicular bundles of the length of 
0-044 millim. ; their anterior third is undulated, the two other 
