ON VERMICULUS LIMQSUS, A NEW SPECIES OF 

 AQUATIC OLIGOCH/ETA. 



By S. HATAI. 



First High School, Tokyo. 



The present species is very common in the muddy gutters and ditches of our 

 city, occurring together with Limnodrilus, Tubi/ex and other Limicolae. It 

 creeps about on the lower surface of fallen leaves and other objects and rarely 

 buries the anterior part of its body in the mud, as do most others ; nor does it 

 swing the posterior half of its body like the latter. The general color is tinged 

 with a milky white and the intersegmental lines are blood red. It is very 

 sluggish, and on being pinched never executes those writhing contractions, but 

 simply retracts its body. These peculiarities serve to distinguish the present 

 species readily from its cohabitants. 



As measured on specimens killed with Perenyi's fluid after stupefying with 

 weak alcohol, the body is 50 — 70 mm. long and 0.5 — 1 mm. wide. The segments 

 number from 120 to 150 in sexually mature individuals. In the anterior part 

 the body is cylindrical, but posteriorly it is somewhat flattened ; the width 

 gradually increases till about the middle of the body, but thenceforward it 

 gradually diminishes. The prostomium is cylindrical and comparatively long. 

 The clitellum is totally absent even in sexually mature specimens, — one point 

 of difference from the known species of the genus, Vtrmiculm piloxus Goodrich. 



The setae are aggregated in bundles, which are arranged in four rows along 

 the length of the body. Each bundle occupies in each segment the four corners 

 of a square, and consists of 5 — 6 setae in the anterior part and 2 — 3 in the 

 posterior part ; the setae being all of the same size. Each bundle contains 

 besides one or two small developing setae in its setigerous sac. The setae are all 

 of the same form, being sigmoid and furcate at the end. There are no penial 

 setae. 



The minute cilia-like processes on the body surface, supposed by Goodrich 

 to be of a cuticular nature, can be observed with high powers ; but in the present 

 species they are closely set only in the posterior part of the body and gradually 



Translated and edited by S. Goto. 



