256 



W. S. NiCKERSON, Oll Cephalog-ouimus vesicaudus u. sp. 



Explaiiatiou of Plates. 



ac acetabulum 



c. V caudal vesicle 



ex excretory vesicle 



g. p genital pore 



i)i intestine 



L. c Laukee's canal 



0. s oral sucker 



ov ovary 



pJi pharynx 



pr prostate 



r. s receptaculum seminis 



tes testis 



vt Uterus 



V. gl vitelline glaud 



Plate 8. 



Fig. 1. Drawing of entire worm as seeü from the dorsal side. Tbis 

 specimen was fixed while flattened under a compressor and the anterior 

 portion is tlius made a little too broad. The outline in Fig. 6 is more 

 normal. 



Fig. 2. A transverse section thru the middle region of the body. 



Figs. 3 and 4. Portions of adjacent sections thru posterior end in 

 direction indicated by the line x — g in Fig. 8. Fig. 3 shows the connec- 

 tion between the excretory and the caudal vesicles ; Fig. 4 shows the 

 opening of the caudal vesicle to the exterior. 



Fig. 5. Part of a section passing transversely thru the caudal 

 vesicle ; the lining layer is represented in only a part of the drawing. 



Fig. 6. Freehand reconstruction of the excretory system of the 

 right half of the worm. 



Fig. 7. Section thru the posterior jDart of the excretory vesicle, the 

 caudal vesicle and the excretory pore, showing the relations of the struc- 

 tures forming their walls. 



Fig. 8. Sketch to show the direction of the plane of section of 

 Figs. 3 and 4. 



