The American Eepreseutatives of Distomum cyguoides. 413 



Worms tliere is likewise great Variation in the size of eg-gs — 

 eyen in the same individual, and in the ripe eggs pressed from the 

 terminal part of the nterus. It becomes necessarj" to select the 

 largest and most normal in appearance. those containing- well 

 developed embryos, and to measure them under exactly the same 

 conditions. Thöt eggs of Gorgodera shrink considerably under the 

 influence of preserving reagents, so that it is necessary to take 

 measurements of the living t^g. Since these views have developed 

 with my experience I am imable to snpply from my notes measure- 

 ments of eggs of all five species that admit of trustworthy comparison. 

 This I shall promise to do later. 



Of External Features the Size, the Shape and the Suckers are 

 valuable for contrast, but the Colour is similar in all — somewhat 

 gray, with suckers and genital organs showing darker. 



Many parts of the Reproductive System are not markedly 

 different from those described for the European species; ovary, 

 oviduct, fertilization space, Laurer's canal, ootype, shell-gland, re- 

 ceptaculuni seminis uterinum, uterus, vagina, sinus genitalis, and 

 porus genitalis; together with the vitelline giands, their ducts and 

 reservoir; and the festes, vasa deferentia, vesicula seminalis, ductus 

 ejaculatorius, and prostate giands are all present in each species; 

 but it is only in the Ovary, Vitellaria, Testes and Uterus that 

 one can ordinarily notice any characteristic diflferences. The 

 latter are especially connected with the size, shape and rela- 

 tive positions of these organs. The absence of a penis-sac, and 

 of a receptaculum seminis, and the small size of the vitellaria are 

 to be noted. 



1. Gorgodera transliicida n. sj). 



This species occurs in the urinary bladder of the toad (Btifo 

 lentiginosus) and also of the green frog {Rana virescens). In the 

 former I have only upon one occasion found it in abundance: this 

 was about tAvo years ago, at Ashbridges Bay, Toronto, the toad 

 harbouring, I should think, between fifty and sixty, mostly of large 

 size — the great number as well as the large size of the parasites 

 Struck me as remarkable. I have not found this form more than 

 two or three times since and then only one or two specimens each 

 time. I have obtained but one rather small individual from the 

 green frog. Unfortunately 1 have been unable to get measurements 



