ENTOZOA. 59 



vided with its proper bursa. The ovaria (f,f) are two in number, of 

 a milk-white colour, situated at the margins of the middle third of the 

 bodj^, exterior to the alimentary tube. They present a dendritic 

 form, small branches being given off chiefly from their outer side. 

 The oviducts run transversely to the middle line, and form there, by 

 their convolutions, a fourth white opake body behind the testes. 

 From this subspherical body the common uterine tube (^) is continued. 

 This is a simple and ample canal, very long and tortuous, occupy- 

 ing all the posterior part of the interspace of the alimentary forks, 

 thence continued forwards with decreasing convolutions, and ter- 

 minating at the vulva. 



The digestive system in the species of Diplostomum, a genus which 

 has two ventral suckers, is as simple as in the Dist. lanceolatum ; but 

 the blind extremities of the two divisions of the alimentary cavity 

 are each lodged in a sac, which, from the milky character of its con- 

 tents, has been termed the chyle receptacle. It is supposed that the 

 nutritious contents of the alimentary tubes exude through the parietes 

 of their ccecal extremities into these receptacles. Two delicate 

 vessels are continued from the anterior and outer angle of each 

 chyle-receptacle, which extend forwards to the anterior third of the 

 body, and are there brought into communication by a transverse 

 vessel, which extends across the dorsal aspect of the body. From the 

 point of union of the transverse with the external lateral vessels, a 

 single trunk is continued forwards on each side to the anterior angles 

 of the body, where they bend inwards and unite in the middle line to 

 form a median trunk, which is continued to the posterior extremity 

 of the body, distributing or receiving branches on each side through- 

 out its entii'e length, and apparently terminating at the posterior 

 excretory pore. Through the connections of this system of vessels 

 with the chyle-receptacles, the terminal pore might be regarded as an 

 anal outlet to the digestive system, and the capillary vessels, ex- 

 tending from the chyle-receptacles to that pore, as a ramified form of 

 intestine, fulfilling at the same time the office of lacteals, lymphatics, 

 arteries, and veins. 



Dr. Nordraann, who has contributed to Comparative Anatomy 

 many excellent illustrations of the vascular system of the Trematoda, 

 was the discoverer of the most extraordinary form in the present 

 class of animals, represented by the species which he has called 

 Diplozoon j)aradoxum. This animal consists, in fact, of two bodies 

 precisely resembling each other, and united, like the Siamese youths, 

 by a narrow communicating band, through which, however, the 

 digestive system of one body freely conmiunicates with tiiat of the 

 other. This digestive system presents the dendritic type of the 



