no p. H. STEWART. 



towards the dorsal wall of tlie anal canal or cloaca. Here 

 they form a layer one cell deep, lying on the cuticular lining 

 of the space, and continuous at the sides with the protoplasmic 

 wall. Since the latter is continuous with the cells of the ventral 

 line, this line may also be presumed to take part in the forma- 

 tion of the ganglion. The cells are of Type 1 . 



The only sensory organs to be found are the hairs above 

 described. They are, as above noted, specially aggregated on 

 the head and in front of and behind the genital apertures. 



To sum up, the nervous system is very imperfectly differ- 

 entiated. The circumoesophageal ring and collar form the brain 

 of the animal; the longitudinal lines, and possibly the sub- 

 cuticula as well, form the conducting paths, both motor and 

 sensory, in the latter capacity receiving stimuli from the 

 sensory hairs. I have not found processes from the muscle- 

 cells to the lines such as occur in other forms ; the motor 

 mechanism is, therefore, obscure. The anal and cloacal 

 ganglia doubtless control deftecation and copulation. 



The Excretory and Glandulau Apparatus. 



Three sets of glands are included in this system : 



(1) The single excretory ventral gland. 



(2) The series of glands of the lateral lines. 



(3) The three tail glands. 



These glands resemble each other in being all nnicellular. 

 The ventral and tail glands have ducts of considerable length, 

 formed by outgrowths of the protoplasm of the cells ; the 

 glands of the lateral lines have no ducts but open directly 

 through the cuticle. 



The ventral gland ^ occurs in males and immature 

 females ; it is absent in mature members of the latter sex. 

 It is composed of one large cell, which lies m the body cavity 

 immediately vcntial to one of the lateral lines, in males on 



^ Golowin (3) lias described this gland in O. vuigaiis. 1 have not been 

 able to procure a copy of iiis jiaper, wliicli is, 1 presume, iu liussian. He 

 regards tlie three "Kcimdriiscu " of the tail as of the same nature as this 

 gland. 



