482 



testes more nearly in the middle line, vesicula seminalis dipping 

 down between ventral sucker and the forking of the intestine, crossing 

 under the left caecum and then turning upwards and forwards to the 

 genital pore. This may be the D. retusum Duj. of Leidy, in Proc. 

 Acad. Sc. Phil. V. p. 207. 



10) Distomum [Haematoloechus] variegatum Rud. Five varieties 

 from the lungs of Canadian frogs and toads — all differing from the 

 European forms. 



11) Distoììium [Gorgodera) cygnoides Zeder. Five forms from the 

 urinary bladder of frogs and toads — differingfrom the European species. 



12) Distomum [Pleurogenes] arcanum. The worm which I pro- 

 visionally placed under the name D. medians Olsson, Zool. Jahrbb., 

 Aug. 1900, is the same which Nickerson, Amer. Natur., Oct. 1900, 

 has figured and described under the name D. arcanum. 



13] Distomum sp. Encapsuled on muscles in posterior part of 

 body-cavity of Rana virescens at Canso N. S. Length 1,3 mm, Breadth 6, 

 Pharynx 12, Oesophagus 15, mouth-sucker 21, ventral sucker 12 in 

 middle of animal. Caeca to half way between ventral sucker and 

 posterior end. Skin with spines. Immature. 



14) Distomum sp. Lung of a snake (Eutaenia sirtalis L.), 

 5X1 mm, spines in skin, ventral sucker one-third back and larger 

 than mouth-sucker. Ends of caeca clasped between testes, which are 

 situated obliquely two-thirds back. Ovary small, right, close behind 

 ventral sucker. Large penis-sac from posterior margin of ventral 

 sucker to genital opening in the fork of the intestine. Vitellaria from 

 near genital opening to posterior testis. The uterus extends almost 

 straight back to posterior end and then runs forwards as a broad sack, 

 filled with dark-brown eggs. Young worms 1 mm long have suckers 

 both of same size and caeca extending only past ventral sucker. 

 Ovary, testes and penis recognizable. Younger ones 0,4 mm long have 

 ventral sucker smaller than mouth-sucker and situated behind middle 

 of body. Rudiments of genital organs and short caeca failing to reach 

 the ventral sucker. 



15) Distomum sp. Oesophagus of same species of snake. 1,65 

 X 0,46 mm. Ventral sucker smaller than mouth-sucker and in centre 

 of animal. Pharynx, long oesophagus, and caeca not reaching 

 posterior end. Genital opening between ventral sucker and the fork 

 of the intestine. 0\ ary behind ventral sucker. Testes, right and left, 

 immediately posterior to the ends of the caeca. Uterus median. \ itel- 

 laria lateral and taking up nearly whole length of animal. Lateral 

 trunks of excretory system evident. 



