216 HENRY LESLIE OSBORN 



in the three genera of the Aspidobothridae we find in Stichocotyle 

 (Nickerson, '95, fig. 23) no recurrent vessel, a ver}^ voluminous 

 collecting vessel and no bladder; in Aspidogaster (Stafford, '96, 

 fig. 15) a partly developed recurrent vessel, moderate collecting 

 vessel, no bladder and two excretory pores; in Cotylaspis (Osborn, 

 '94, figs. 5 and 26) a fully developed recurrent vessel, a small 

 collecting vessel and two well developed bladders. So that it is 

 impossible to attach any phylogenetic value to differences shown 

 in the organization of the excretory system. 



THE REPRODUCTIVE SYSTEM 



My observations are in substantial accord with those of Looss 

 and MacCallum with regard to the chief facts in the anatomy of 

 this system. Figs. 1, 2 and 3 show the parts in situ as they ap- 

 pear in various sectional planes. Fig. 17 is an outline of the 

 organs based largely on a study of the total preparation from 

 which fig. 1 was drawn. The two testes lie in the last body third; 

 ovary, shell-gland and ootype, oviduct, Laurer's canal and yolk 

 receptacle are all compactly grouped in the space between the 

 testes. There is a peculiar uterine sack in the course of the uterus, 

 the yolk follicles are small and very diffuse. Since no detailed 

 account of the members of this system has ever been given I will 

 give here a brief description of it. 



Genital pore. The genital pore lies in the mid-ventral line (fig. 

 4 E). Its distance from the anterior end has been considered 

 already in this article. There is an atrial cavity below the surface 

 from which a single pore opens to the exterior. The relation of 

 these parts is shown in figs. 3 and 4 E. 



Cirrus sack. MacCallum's figure shows the cirrus sack and its 

 contents very adequately. The sack occupies a position on the 

 right side of the animal in front of the anterior testis. At its 

 posterior border it receives the two vasa deferentia. The wall of 

 the sack is supplied with muscles whose powerful fibers lie so as 

 to form a circular and longitudinal coat. The sack contains a 

 tube of varied diameter, coiled so as to accommodate its length to 

 that of the sack. Posteriorly the tube expands to a larger, thin- 

 walled, non-muscular seminal vesicle filled with spermatozoa. 



