BY S. J. JOHNSTON. 329 



Laurer's canal, a canal with muscular walls, opens on the 

 exterior about the middle of the dorsal surface, opposite the 

 middle of the ovary. It skirts round the right side of the ovary 

 and opens into the proximal end of the ootype. In its interior 

 a number of sperms can be seen. The canal is quite large enough 

 to be used in copulation. 



The most characteristic features of the worm are its size, the 

 character and position of the suckers, the folded but unbranched 

 intestine, the ovoid shape of the ovary and testes and their 

 situation, the great length of the uterus, the grape-like vitelline 

 glands, and the well developed excretory system. 



The simple nature of the intestine, the absence of hooks or 

 lobes from the suckers, the almost total obliteration of the 

 oesophagus, and the absence of a retractile telescopic tail part 

 indicate the position of this species to be in Dujardin's subgenus 

 Brachylaimus. 



In external characters, as general shape, size, character and 

 position of the suckers and transversely striated appearance, it 

 closely resembles D. veliporlum, Creplin, found in the American 

 barn-door skate, Eaja kevis, in Prionodon milberti, and in Hexar- 

 chus g7'lseus. In its internal anatomy it shows a fairly close 

 resemblance to D. tereticolle, Rud. The excretory system is very 

 marked and very similar in each. The limbs of the intestine in 

 D. tereticolle are without the folds shown in D. irristio'pliori. 

 They both have the uterus long, slender and much folded, and a 

 similar structure, arrangement and amount of development in the 

 vitelline glands; in this new species the ovary and testes are 

 situated much nearer together. 



The figures for the plate were drawn by my wife. 



EXPLANATION OF PLATE XIIL 



Distomum pristiophori. 



Fig. 1. — View of the whole animal ( x 6). 



Fig. 2. —Transverse section through the middle of the ventral sucker ( x 15) 

 Fig. .3. — Transverse section through posterior end showing the large excretory 

 vesicle ( x 20). 



