556 FRANK E. BEDDARD. 



Besides the minute orifices of the unicellular glands of the 

 epidermis (fig. 3), which here, as in other species, show a 

 cross-like form illustrated in many memoirs upon the anatomy 

 of earthworms, there were other larger orifices of a circular or 

 perhaps slightly elliptical form. In the figure cited the number 

 of these apertures relatively to those of the unicellular glands is 

 shown ; they are extremely numerous in each segment, and have 

 no particular regularity of arrangement. 



These apertures obviously suggest the external pores of the 

 nephridia, which are so numerous in Perichseta and other 

 forms with difi'use nephridia. In Perichseta the apertures 

 in question are of moderate size, though considerably smaller 

 than the apertures through which the setse protrude. They 

 are continuous with a little cylinder of chitinous membrane, 

 which is, of course, the lining of the nephridial tube. 



In Libyodrilus the apertures that I have referred to were 

 smaller than those ofPerichseta, and I could not detect the 

 involution of the chitinous membrane. Otherwise I should 

 have thought myself justified in stating, if necessary without 

 any further investigation, that Libyodrilus belonged to that 

 group characterised by a diffuse, irregular nephridial system. 



This suggestion, however, appears to be somewhat at variance 

 with the statement that Libyodrilus, like other Eudrilids, 

 possesses paired nephridia, one pair to each segment. I have 

 found, however, by a series of sections, that the body- wall is 

 permeated by a sy st em ofb ranching and anastomosing 

 canals, opening on to the exterior by numerous aper- 

 tures, and connected on the other hand with the 

 paired nephridia. I took these canals at first for blood- 

 vessels, to which they bear not a little resemblance ; indeed, I 

 am still unable to find any very marked histological difference 

 between these tubes and the blood-vessels. That they belonged 

 to a different system was shown by the fact that they were 

 frequently found to be accompanied by blood-vessels. It is 

 hardly perhaps necessary to say that there was no connection 

 between these tubes and the blood capillaries; the former never 

 contained blood-clots, while it was impossible to follow out a 



