278 Henry Leslie Osborn, 



suppose that their contents are discharged by contractions of these 

 muscles. The ultimate capillaries and flame cells of this system 

 have not yet been recognized. 



A Y-shaped excretory bladder is found in other members of 

 this sub-family, as for instance in D. medians (Looss, 1894, fig. 36) 

 and D. confusus (Looss, 1894, fig. 33), and also in various non-related 

 forms. 



The Reproductive System. 



The testes lie opposite and in the level of the centre of the 

 body. Thej?^ are elliptical in outline and their margin is entire. 

 Their maximum diameter measures about 0,4 mm. The worms found 

 in the frog were fully matured and the testes contained great numbers 

 of spermatozoa, and later stages of spermatogenesis. There is a 

 large cirrus sack, which encloses both the seminal vesicle and 

 ejaculatory duct. It lies on the left side of the body ventrally to 

 the intestine and passes obliquely forward and outward from a 

 point near the inner anterior border of the left testis to the genital 

 pore. The cavity of the seminal vesicle is filled with spermatozoa. 

 The ejaculatory duct cuticle is spinous, contrary to most trematodes. 

 Beaun (1893, p. 737) says on this point, „Die Geschlechtscloake er- 

 weist sich als eine mehr oder weniger tief erfolgte Einsenkung der 

 Körperwand, welche abgesehen von dem Begitze von Stacheln, 

 die Structurverhältnisse jener ziemlich getreu wiederholt." A de- 

 tailed account of these spines follows later in this paper. 



The ovary lies on the right side of the body, near the median 

 line, and on the same level as the testes and between them. It is 

 internal to the right intestinal coeca and only slightly anterior to 

 the ventral sucker. As to outline the ovary is conical. Its apex 

 points inward and backward. The base is slightly lobed but the 

 lobes are not so deep and so numerous as those shown in Nicker- 

 son's figure. The oviduct at once passes through the so-called shell 

 gland, and communicates with the passage from the seminal recep- 

 tacle and Lauber's canal. Laurer's canal passes dorsally to reach 

 its opening at a point almost directly dorsal to the ventral sucker. 

 The uterus crosses over to the left side of the body where its 

 proximal loops remain. These reach forward and backward several 

 times and finally the tube crosses posteriorly in the body to the 

 right side where a second system of loops make up its distal end. 

 The uterus then runs obliquely forward to the genital pore. The 



