448 THOS. H. MONTGOMERY jr., : 
The receptaculum seminis. This long sack (Rec Figs. 78, 
79, Pl. 42) connects by its constricted posterior end (neck, Rec. N) 
with the atrium (Atr), and extends forward in the medio-ventral line 
above the nerve cord, displacing the intestine (Int) from its usual 
position, so that the latter is either forced to one side of or above 
the receptaculum. It is much folded (Rec Fig. 66, Pl. 41) when not 
filled with spermatozoa, but when so filled (Rec Fig. 68) rounded and 
of much greater diameter. Its wall (Fig. 53, Pl. 40) consists of a 
flattened epithelium {with disc-shaped nuclei (N) and vacuolar cyto- 
plasm; in the constricted neck region the epithelium is much folded 
and the lumen almost obliterated (Rec. N Fig. 70, Pl. 41). Encircling 
the neck is a sheath of small-celled parenchym (S. Par) which diminishes 
in thickness anteriorly so that the larger portion of the receptaculum 
is bounded laterally only by the thin dorso-ventral mesenteries, which 
are modified anterior continuations of the small-celled parenchym. 
Structure of doubtful importance. In two individuals 
only there was found in the mid line, imbedded in the parenchym 
between the intestine and the neck of the receptaculum seminis, a 
saccular structure (X Fig. 70, Pl. 41; Fig. 79, Pl. 42) with a flattened 
cellular wall and vacuolar fluid contents, but with no opening into 
either the intestine (Int) or the receptaculum seminis (Rec), though it 
comes into contact with both these organs. ‘The lining epithelium of 
this organ has somewhat the same character as the wall of the in- 
testine in this region of the body. This probably represents some 
organ, or part of an organ, which is functional at an earlier stage 
only, and may be a diverticulum of the intestine. 
The cloaca. This (Gl. Cl, Cu.Cl Figs.. 78, 79, Pl. 42) is an 
axial cylindrical tube, narrowest anteriorly and gradually enlarging 
posteriorly, which extends from the posterior end of the atrium to 
the posterior end of the body. The cloacal aperture is the space em- 
braced by the three divergent tail lobes, and at their ends the epi- 
thelium of the cloaca passes continuously over into the hypodermis of 
the external surface of the body. Paragordius differs most markedly 
from Gordius and Chordodes in respect to this organ, for while in 
the latter genera the cloaca is exceedingly short, in Paragordius it 
reaches a length of than 6 mm. The length of the cloaca in its 
relation to the neighboring parts of the genital apparatus is shown in 
Fig. 78. It not only serves as the canal for the entrance of the 
spermatozoa to the receptaculum and for the passage of the ova to 
the outside of the body, but also for the discharge of the contents of 
