CALIFORNIA EUDRILIDA, 17 
begins at the point of recurrence at @); but ceases after the duct has assumed its straight 
course at (8); it begins again at (@), and is with a certainty found between (©) and 
(@), and possibly between (@) and (2), where, however, I am not quite certain of 
its presence. The whole nephridial fold is imbedded in a wing-like cellular and 
fibrous mass, which at either end becomes thicker, supporting large pellucid perito- 
neal cells, such as found in the nephridia of many Oligochieta (fig. 64, per. c.), and a 
complex system of blood-vessels, which branch and form capillary ioops partly on the 
folds, but principally between the spongy tubes and the two central canals (figs. 59, 
63, 64, 67, b/.). The blood-vessels originate from a branch of the ventral yessel as in 
Lumbricus. 
Scattered over the peritoneal cells are masses of free cells, generally agglom- 
erated in separate heaps. Each cell is deeply crenate, as if it consisted of several in- 
dividual cells, but in each such small agglomeration there is only one round nucleus 
(fig. 80). 
If we recapitulate, we find that the nephridum of Argilophilus consists of the 
following distinct part from the nephridio-stome to the nepridio-pore: 
1. Nephridio-stome, engaged in the anterior septum. 
2. Narrow duct, which connects the nephridio-stome with the body of the ne- 
phridium proper, especially with the spongy tubules. 
3. Spongy tubules, which are at first irregular, but which soon fuse into one 
main-tube with many branching tubules. 
4. Main nephridial canal, which, recurring on itself several times, forms two 
distinct folds and one spur. The posterior fold contains besides the tube and tubules 
two turns of the canal, one of which is recurring. The anterior fold contains three 
turns of the canal, two of which are recurring. Part of this anterior fold disengages 
itself from the main nephridial mass and forms the 
5. Spur. This spur contains four canals, two of which are recurring, the 
point of recurrence for all four being at the distal end. One of the recurring canals 
of the spur is connected with the posterior fold by the 
6. Bridge, a part of the canal much narrower than the other, spanning the 
distance between the two folds. 
7. The wide duct leading to the nephridio-pore, directly connected with the 
recurring canal of the posterior fold. In different nephridia this wide duct is of 
varying length. 
8, Nephridio-pore, apparently without urinary bladder or collar. 
9. A large wing-like, but rather thin, mass of peritoneal cells. 
10. A complicated and extensive system of capillary blood vessels on the va- 
rious parts of the nephridium. 
Compared to the nephridium of Lumbricus as described by Benham we find 
a few more important differences, especially in the post-septal part. Thus the post- 
septal part of the narrow tube after reaching the first loop assumes the shape of a 
