16 



four very fine vessels. M. Van Beneden, of Belgium, 

 considers them as urinary vessels. Is it not possible 

 that they may have been confounded with the nutri- 

 tive system] The description answers well. 



The nervous system of these parasites is a subject 

 of interest and much doubt, being described as con- 

 sisting of two cerebral ganglia united by a slender 

 commissure, from which long cords go off upon each 

 side of the articulations (nutritive system ? ). It has 

 also been stated, that at the base of each disc is a little 

 ganglion, which communicates with the cerebral ones. 

 M. Dujardin does not view these lateral cords as 

 nerves, but rather as ligaments (Moquin-Tandon). 



The skin is soft, nearly white, rather tough, and 

 consists of a corium, thick and fibrous, and of an 

 epidermis. Beneath these there are muscular fibres, 

 both longitudinal and transverse (Kiichenmeister), 

 which are not interrupted at the borders of the ar- 

 ticulations. 



We have already seen that the ova are contained 

 in the older joints only (about the 700th), and that 

 those near the posterior end of the entozoon are the 

 ones which are fecundated. This is performed by the 

 intromission of the male organ into the female open- 

 ing. 



The eggs (PI. I. fig. 3, B) which are thus fecun- 

 dated are 0-036 mil. in diameter, round, and rather 

 whitish, and consist of two or more shells, the outer- 

 most of which is chitinous, either thick and composed 

 of many small granules, or thin and membranaceous. 

 Only those which are matured possess the two shells ; 



