368 TREMATODE FROM HEN'S EGG, 



ova were also seen lying behind the testes. One ribbon-like mass of 

 ova marked the position of one of the convolutions of the oviduct. 



Behind the testes the superficial tissue could be seen to be reticulated 

 •with the transparent anastomosing vessels of the water-vascular system 

 leading finally to a terminal pore. 



The penis can be traced from the point \There the intestine divides, 

 forward to the left side of the oval sucking-disk. The whole surface of 

 the body is somewhat rugose. 



The outline and proportions of the different organs are sufficiently 

 shown in the figure. In order to obtain further details it would be 

 necessary to stain and sectionize. 



Following are measurements made on the alcoholic specimen : 



Millimeters. 



Length 7 



Breadth at ventral disk 2. 1 



Breadth at widest part "2. 8 



Diameter of oral disk 5 



Diameter of apertnie of same 245 



Diameter of ventral disk 805 



Distance between centers of disks 1. 925 



Length of testis 2 



Breadth of testis 1 



Length of ova , 024 



Breadth of ova 013 



Tlie ratio of the diameter of the anterior to the posterior sucking-disk, 

 while less than that given by Von Linstow for i>. ovatum, viz, 1 : 2.1, 

 coincides more nearly with it than it does with the ratio 1 : 1, given by 

 the same author for his species D. pellucidmn, from the oesophagus of 

 the domestic fowl. 



The vitellaria, since they barely extend to the posterior edge of the 

 ventral sucker, are more decidedly like those of D. j^ellucidum than of 

 D. ovatum. 



Distomum ovatum Eud., from white of Eo-wly-laid hen's egg. Ventral vie>v, enlarged 10 diameters 



Sketch by M. B. Linton. 



Distomum ovatum Eudolphi is a well-known Trematode, and has been 

 recorded as occurring in a variety of avian hosts,* 



* Cobbold, in his Synopsis of the Distomidce [Journal of the Proceedings of the Liu- 

 nean Society, Zoology, Vol. V, 1861], gives the following with regard to the habitat 

 of this parasite : 



"This species has been observed outside tlie intestine of the domestic goose {Anas 

 Anser) by Miiller, and in the Bursa of Fabricius in the following species : In A. clyp- 



