248 FRANK E. BEDDARD. 
The nephridia commence in the 16th segment. They open 
on to the exterior by the second seta. They are clothed with 
a thick layer of peritoneal cells. 
The question now to be considered is the family into which 
this new type should be placed. That it is generically distinct 
there is in my opinion no doubt whatever. This genus Allu- 
roides is one of those forms which render the distinction 
between the old groups of the “ Limicole” and the “ Terri- 
cole”? untenable. In some respects it is even more perfectly 
intermediate than Moniligaster. 
Aside from Moniligaster, the “waterworms,” all of them, 
differ from any earthworm in the following characters : 
1. Clitellum one cell thick. 
2. Ova very large and full of yolk, few in number. 
3. Genital aperture situated far forwards. 
4, Egg-sacs occupy more than one segment. 
These are positively all the distinguishing marks if we leave 
aside the genus Moniligaster. Moniligaster itself, as I have 
shown in several papers! dealing with the structure of this re- 
markable worm, breaks down the first, third, and fourth of the 
above distinctions. Moreover, it has eggs which, although they 
are not greatly above the average size of the eggs in earthworms, 
differ from those eggs in containing a great quantity of yolk in 
the form of large spherules. Moniligaster, in fact, is only 
an earthworm in having a gizzard or rather gizzards, and in 
the comparative thickness of the body-wall. This latter 
character, however, is seen in Phreoryctes, which is one of 
the genera assigned by Claparéde to his division Limicole. 
Besides the points enumerated in the above tabular statement, 
Moniligaster has various other resemblances to several 
Limicolous Oligocheta, which are not of first-rate importance 
from the present point of view, inasmuch as they also occur in 
other earthworms, though not to so marked a degree. The 
atrium, for example, is almost exactly like that of the Lumbri- 
culide. ‘'The protrusible penis is constructed more on the lines 
1 For a list of literature see ‘‘ Description of New or Little Known Earth- 
worms from various localities,” ‘ Proc. Zool. Soc.,’ 1892, p. 690. 
