TWO AQUATIC OLIGOCILETES. 



45 



There are no pharyngeal nerves. 



The anterior sperm-sacs are paired. 



The posterior sperm-sac reaches 

 sometimes to segment XVI. 



The prostate opens narrowly into 

 the atrium. 



The duct portion of the atrium is 

 about half as long as the atrium, 

 and its inner epithelium is not 

 ciliated. 



The wall of the penis is incom- 

 pletely two layered. 



*The chitinous penis sheath is 

 10-11 times as long as its diameter 

 at the proximal end. 



The muscle fibres surrounding the 

 male copulatory apparatus are spiral. 



*Spermatophores are not present. 



*The prostate is of irregular shape. 

 No septa in the intersegmental 

 lines I/I.I and II/III. 



The two septal sacs of a septum 

 open separately. 



The prostomial ganglion is 0.015- 

 0.02 mm. long and 0.008-0.01 mm. 

 broad. 



Blood corpuscles are very few or 

 entirely wanting. 



One pair of strong pharyngeal 

 nerves run out from the posterior 

 corners of the brain. 



The anterior sperm-sac is unpaired. 



The posterior sperm-sac is confined 

 to segment XI. 



The prostate opens widely into 

 the atrium. 



The duct portion of the atrium is 

 longer than the atrium, and its 

 inner epithelium is ciliated. 



The wall of the penis consists of 

 two layers throughout. 



*The chitinous penis sheath is 

 3-4 times as long as its diameter 

 at the proximal end. 



The muscle fibres surrounding the 

 male copulatory apparatus are straight 

 and parallel to the long axis of the 

 penis. 



*Spermatophores are always pre- 

 sent in the spermathecse. 



*The prostate is spindle shaped. 



Septa I/II and II/III incomplete, 

 being present only on the ventral 

 side of the intestine. 



The two septal sacs of a septum 

 have a common opening. 



The prostomial ganglion is nearly 

 twice as large as in L. gotoi. 



Blood corpuscles are very numer- 

 ous. 



Characters marked with * are easily observable in the living 



state. 



Comparing these two Japanese species with the European 

 and American, as described or diagnosed by Eisen, Vejdovsky, 



