82 CALIFORNIA ACADEMY OF SCIENCES. 
eral description of them will be superfluous. The spur is directed backwards and the 
two folds are directed upwards in about right angle to the spur and narrow duct as 
well. The spur and the folds rest on the large lobes of peritoneal cells, one of which 
is posterior and one anterior. The posterior one surrounds the spur, upon the ante- 
rior one, which is the smallest, rests the two folds. The narrow duct is not unusually 
narrow, while the wide duct or outlet duct is very narrow, not any wider than the 
narrow duct. The neck of the anterior fold is, where it connects with the nar- 
row duct, very wide, enlarged, irregular and sigmoid, gradually increasing in size to 
the anterior fold. Where the two folds join, the fold is always very coiled. The tube 
forming the bridge is not any wider than the clear canals, but it is less clear or trans- 
parent, just as in Lumbricus. The canal leading from this bridge into the anterior 
fold, is straighter, darker, and slightly wider than the two bright tubes which are 
much coiled and situated more anteriorly and superiorly to the straighter canal. This 
coiling ceases as soon as the big bend and windings are passed and the posterior fold 
is reached. 
The nephrostome is large. The marginal cells in the rosette are only slightly 
decreasing in size toward the extremities or centripetal marginals. There is a large 
centripetal protuberance surrounding the inner opening of the duct, as in Lumbricus. 
as described by Benham, but the centrifugal cells are less regular and more scattered, 
The centrifugal cells are never hidden by the centripetals as in Lumbricus, and the 
whole centripetal protuberance is most prominent seen in whatever direction. ‘The 
outlet duct enters the fold much closer to the narrow or nephrostomal duct than is 
usual in Oligocheeta, in fact it connects with the free neck of the anterior fold, close 
behind the septum. 
The relationship of Pontodrilus Michaelseni to the other species of the genus 
is not as clear as we might wish. Beddard’s description and notes in his paper, 
“V. Some new or little known Oligocheta,” are the only comparative remarks yet 
made on the few worms which are grouped under this genus, an arrangement which 
must be considered as entirely preliminary. The only very characteristic features 
which connect the six species of the genus is the commencement of the nephridia 
posterior to somite xii, and the opening of the spermduct into the prostate, absence 
of typhlosole, grape-like sperm-sacs, and no penial sete. None of these species 
have been sufficiently described, an unavoidable fault attendant all species im- 
mersed in alcohol without previous careful preparation and evacuation. In the 
following table I have endeavored to compile the characters of the various species as 
far as I can make out fromthe descriptions, no specimens for comparison being in my 
possession. I include here, as suggested by Beddard, the genus Photodrilus Giard. 
I have had no access to Grube’s description of P. littoralis, and have therefore 
excluded it from this table. 
