Jlieringula paulensis, a new generic Type of Macrothricidæ. 23 



eimens, as usual, the contents of the ovaries are of a much 

 darker colour, and each ovary contains only the material for 

 a single ovum. 



The number of ova and embryos contained in the in- 

 cubatory cavity of parthenogenetic specimens, varies according 

 to the size and development of the individuals, and is gene- 

 rally greatest in the first generations appearing, amounting 

 sometimes to a dozen or more. In specimens of the later 

 generations, the number becomes much reduced, and is often 

 restricted to only 2. 



The testes in fully adult male specimens (PI. I, fig. 6) are 

 very conspicuous, forming on each side of the intestinal 

 tube a rather large elongated sac extending through the 

 greater part of the trunk, and divided by transverse con- 

 strictions into several successive compartments. From the 

 hindmost of them a narrow duct originates, extending down- 

 wards along the anterior side of the tail, and debouches, in 

 close approximation to that of the other side, on the above- 

 mentioned small prominence just in front of the caudal claws 

 (see PI. II, fig. 14). The zoosperms are in the form of very 

 small nucleated cells (fig. 15). 



Biological Observations. 



The present form was raised in considerable numbers in 

 some of my aquaria, and has been watched during 2 suc- 

 cessive seasons. As is generally the case, at first only a few 

 specimens appeared, being hatched from the ephippia con- 

 tained in the dried material; but these, after having at- 

 tained their full development, rapidly multiplied in the usual 

 parthenogenetic manner, several successive generations ap- 



