PACIFIC COAST OLIGOCH ®TA. 85 
connecting the former with, third, the posterior one, a storage chamber for sperm- 
atozoa, 
Spermducts are two pairs, exceedingly narrow, opening close together in the 
posterior part of the storage chamber. 
Ciliated rosettes, two pairs, the anterior pair opening in ix. The posterior pair 
in x, both in front of the septum. They are exceedingly thin and flat. The posterior 
wall is attached to the septum. 
Sperm-sacs consist of a pair of very long continuous sacs, which cover the 
generative organs, including the spermatheca, and extending from somites x to xvii 
or xviii, generally several somites posterior to the caudal part of the storage chamber. 
Setw are 8 in 4 pairs in each somite, commencing with the second. 
The vascular system is characterized by blind forked vessels in the posterior 
30 odd somites, thus bringing the genus in close relationship with Lumbriculid:e. 
Another characteristic is the two loops of lateral vessels which branch out from the 
main vascular trunks in somites ix and x, and which run backwards as far as the end 
of the storage chamber. The anterior eight somites contain winding lateral yessels 
connecting the two main dorsal and ventral trunks. Hertzkorper in the dorsal vessel 
as well as in the branches in the intestine. After these preliminary references to 
the main anatomical points I will enter more fully upon the anatomical and_histo- 
logical structure of the various organs. 
Body-wall and Chitellum. The finer structure must be left for future study. 
The inner longitudinal muscular layer is considerably thicker than the transverse 
layer and hypodermis together. The longitudinal strands are very thin and ribbon- 
like, some being much longer than others and reaching through the width of the 
layer, others being very much smaller, situated principally close to the transverse layer. 
Figs. 77, 79, 99, ete. 
The clitellum comprises about 6 somites, commencing in the posterior part of 
ix and extending to the center or posterior part of xiv. The clitellar glandular 
cells, one layer thick, are oblong, irregular, flask-like, containing very coarse, angular, 
grains (fig. 79). They are separated or interspersed by large non-staining cells. 
The peritoneum is rather poor in blood vessels, but the layer is very thick, in places 
almost as thick as the longitudinal muscular layer (fig. 82, pr). 
Septa. None of the septa are abnormally thickened. The first distinct sep- 
tum is seen between somites v and vi. The septa are st ‘aight, not cup-shaped. Those 
surrounding the various divisions of the prostate are much firmer than the others. 
They constrict the prostate, in fact the latter appears notched at every septum 
(figs. 78, 92, 94). 
Alimentary canal. The alimentary canal can properly be only divided in two 
parts—pharynx and intestine. The pharynx which ends in somite v is developed 
latterally and dorsally, but not ventrally (figs. 83, 77). The thickened part is very 
thick, consisting of the usual narrow and almost filiform cells. The ventral part is 
