CONTRIBUTIONS TO THE ANATOMY OF EARTHWORMS. 441 
is lined with a tall columnar ciliated epithelium. 
The ciliated cells showed the usual refracting band just below 
the cilia. The cells did not seem to be all ciliated. There 
were ciliated tracts here and there. As far as I am aware, 
cilia have never been shown to exist in any part of the 
spermathece of Oligocheta. The statement of Buchholtz 
that the glandular appendices of the Enchytreide are ciliated 
is believed by Vejdovsky (39) to be a mistake, spermatozoa 
having been taken for cilia. The ciliation of this portion of 
the spermathecz is so far favorable to the supposition that 
the diverticula are mesoblastic structures, that it is only meso- 
blastic and hypoblastic structures in Harthworms which show 
any ciliation. It may be that the ciliated canal is the rudi- 
ment of an oviduct, and the structure of Eudrilus and 
Teleudrilus are favorable to this view. It must be admitted, 
however, that a good many more facts must be discovered 
before this view can be regarded as in any way established. 
On the Classification of the Species of 
Acanthodrilus. 
We are at present acquainted with twenty species of 
Acauthodrilus,! which show a considerable amount of 
specific variation. The principal points in which the species 
differ are—(1) Number of segments occupied by clitellum ; 
(2) arrangement of setz; (3) characters of excretory system ; 
(4) paired or single dorsal vessel; (5) number and characters 
of the spermathecal appendices. There are also several minor 
differences, such as the form of the buccal lobe, the presence 
of one or two gizzards, the alternation in position of the 
nephridial apertures where there are only one pair per segment, 
the ornamentation of the penial setz, &c. 
These characters render it possible to arrange the species in 
several groups, to which, however, I do not thing it advisable 
to give generic names. 
1 Excluding Benham’s Trigaster Lankesteri, which Horst thinks 
should be referred to the genus Acanthodrilus. It is, in my opinion, not, 
yet necessary to make this change. 
