PACIFIC COAST OLIGOCH MTA. 173 
Sete strictly paired, sigmoid plain. The pair 1 and 2 is wanting in xvi. 
Spermathecal pores in ix in front of setee 1 and 2. 
Oviducal pores in xiy in front of sete 1 and 2. 
Spermaducal pores in the center of xvii, where otherwise would be the sete 
land 2. A small copulatory papilla around each male pore, but it is not connected 
with a zone. No dorsal pores. 
INTERNAL CHARACTERS. 
Muscles. Numerous arciform muscles in the copulatory region, but especially 
in xvii, connecting the copulatory papillse with the body-wall in line with sete 3 and 4. 
These arciform muscles are arranged in three distinct groups. The central group, 
which branches out fan-shaped from the inner surface of the copulatory papillie, is by 
far the largest, consisting of about 10 to 12 distinct fascicles. Anterior to this is 
another group of 6 to 7 fascicles, and in the posterior part of the somite we find a 
swollen group of about 5 fascicles. To what extent these vary as to numbers, ete., is 
uncertain, but my observations in Phanicodrilus taste are that they are quite constant, 
and might be used as valuable characters in determining the species, as with a change 
in the muscular strands is also connected one in the exterior copulatory zone. Between 
xvii and xiii, as well as between xvii and xix we find several pair of arciform muscles 
in each somite. 
Septal glands are well developed. The suprapharyngeal glands are very jong 
and extend far backwards. ‘The septal glands in the following somites diminish 
posteriorly. 
Spermathece. One pair in ix open between viii/ix in front of sete 1 and 2. 
Form sac-like, very thin walls, pellucid, outline smooth, without any warty diverticula. 
No distinction between a muscular and glandular part. The size is large, about as 
long as the somite is wide. 
Testes, ovaries and ciliated rosettes not characteristic. 
Ovisac. There is a median ovisac in xili/xiy (fig. 157), consisting of a 
pouching backwards of part of the septum. ‘This is the only species in the three 
genera, Ocnerodrilus, Gordiodrilus and Pheenicodrilus, which possesses an ovisae. 
Spermducts are of the same width throughout, without any muscular enlarge- 
ment near the male pore. The two ducts run together, but their lumens are separate 
until they reach the muscular atrium, where, just before they enter it, the two lumens 
fuse into one (figs. 158, 159). 
Muscular atrium. As has already been stated the usual prostates in Ocnerodrilus 
are replaced by a pair of muscular pouches, entirely covered up by the numerous 
arciform muscles. There are no glandular cells, and these atria can best be compared 
to the basal muscular parts of the Oenerodrilid prostate only they are yery much 
thicker, and consist entirely of muscular cells with the lumen in the body-wall lined 
by columar epithelium. In the main pouch this epithelium consists of short cells with 
round nuclei, around which extends a thin musenlar layer, which becomes wider at 
the base. This atrium is very short and cannot readily be seen when the opened 
