702 MacCALLUM. [Vol. XV. 



this part of the tube and the dilated portion which follows, and 

 which has a peculiarly modified cuticular lining. This dilated 

 portion of the tube is surrounded by a thick layer of deeply 

 staining cells very closely resembling those found in the general 

 subcuticular tissues. The cuticular lining is furnished with 

 large, highly refractive polygonal masses of cuticular substance. 

 In sections these are sometimes detached. The subcuticular 

 circular musculature is disposed much as it is in the general 

 body surface. Narrowing again, this dilated portion passes to 

 the external orifice, which is a crescentic slit immediately behind 

 the opening of the female apparatus. 



In the testes there is a somewhat alveolar structure, and the 

 formation of spermatozoa seems to take place by the production 

 of a morula-like mass from the dividing cell, the division prod- 

 ucts of the nucleus being peripheral ; by the disintegration 

 of this mass, as each nuclear particle is provided with a 

 certain portion of the protoplasm, a number of spermatozoa 

 are formed. 



The female apparatus consists of an ovary, yolk-gland, 

 Laurer's canal, and uterus, with their connecting ducts. The 

 ovary is triangular and situated between the two testes on 

 the right side. It is quite small, being less than one-fourth the 

 size of either testis, and has a median position dorsoventrally 

 in the body. It is somewhat lenticular in cross-section. The 

 ciliated oviduct runs upward and forward from its anterior por- 

 tion to join the other ducts leading to the uterus. The vitel- 

 larium, beginning at the level of the middle of the acetabulum, 

 and e.xtending back to the posterior end of the body, is made 

 up of separate acini which send ductlets to form a transverse 

 duct on each side, and these transverse ducts uniting in the 

 center form a somewhat ventrally placed dilatation or reservoir. 

 The nuclei of the cells making up the yolk-gland stain deeply 

 with haematoxylin, while the yolk-granules stain brightly with 

 eosin. 



From the yolk-reservoir there are given off two tubes, one 

 of which, running laterally, is thick-walled and widens into the 

 uterus. The other tube runs forward and upward (this also 

 is thick-walled and ciliated), and at a point where it becomes 



