218 M. E. Claparede on a new Genus 



into a cavity which may be regarded as the buccal cavity, and 

 from this into a straight muscular oesophagus, 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 oesophagus 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 ^^^^ or rarely two at a time. After laying 

 this e,ggy and before producing a new one, it loses temporarily 

 all the characteristics of the female 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 



