PACIFIC COAST OLIGOCH MTA. 87 
Spermatheca. As stated there is one pair situated in ix, the spermathecal pore 
being posterior to the sete, and in line with the inner couples. The spermatheca 
consists of two distinct parts, as is usual in this group, the lower muscular part, and 
an upper rounded part consisting of an unicellular layer of dice-shaped cells. This 
rounded chamber was sometimes situated in the same somite, ix, as the muscular 
body, but frequently it projected backwards into somite x. 
The structure of this muscular part is represented in figure 82. The inner epithe- 
lial layer, consists of narrow columnar cells, with rounded nuclei and striated proto- 
plasm. Exterior to this layer, there is a thin one of transverse or circular muscles, 
outside of which again is an epithelial stratum one or two cells deep, with slightly 
oblong nuclei, the cells themselyes being irregularly dice-shaped (fig. 82). 
Prostate and spermducts. The most interesting, as well as the most complicated 
structure of this species, is the prostate, of which I am now able to give a fuller ac- 
count, which J believe will not leave any of the points of its structure in doubt. 
I have already referred to the three main divisions of the organ, the proximal 
one consisting of a long cylindrical tube, containing penis, atrium and _ prostate. 
Second, a very narrow tube of almost the same structure as the prostate part of the 
former, connecting with a long cylindrical chamber of somewhat modified structure, 
into which the two spermducts open, quite near its junction with the narrow part or 
bridge. If we, however, disregard the difference in size of these various parts and 
only consider the structure, we find that the whole organ may also be divided in 
three parts: 
First, the proximal part, which is entirely confined to somite x. This part is 
upright, so to say, does not run backwards; it is also somewhat bent, forming a right 
angle with the balance of the organ. This part consists of penis, and a long tubular 
part which, in want of a better name, I designate as atrium (fig. 100 air. and p.). 
With somite xi commences a change of structure of this organ, common both to the 
wide part and to the very narrow posterior part. I will refer to it as the prostate 
proper, as it contains the thick layer of regular prostate cells so common in all higher 
oligocheeta where this organ occurs; it is the “two layer”’—prostate of Beddard. The 
third part or storage chamber is characterized by the absence of this layer. 
I will now refer to each one of these three or four parts in succession and more 
in detail, beginning with the penis and atrium. 
Next to the body-wall, ending at the transverse muscular layer and from there 
stretching inwards, is a reversible sae—a preputium 
with very large, round, compressed nuclei and striated contents. This epithelium is 
surrounded by a thin muscular layer (fig. 100, pre., 101). 
Into this preputium opens a penial glans (fig. 100 p. g/s., 101, etc.), consisting of 
two separate covers, posteriorly attached to a collar of larger rounded or pear-shaped 
cells, at the base of which are seen a number of muscular plates. This collar is 
folded on itself, one part of the fold connecting with outer and one part with the 
inner cover of the glans. Through the median line of these parts runs a long, very 
5 
consisting of epithelial cells, 
Memorrs, Vou. II, 4. February, 1895. 
