( 248) 
EXPLANATION OF PLATE XIV. 
a = ampulla of spermatheca. 
a' = ampulla of other side. 
at = atrium. 
at.s = atrial sac. 
(I = dilatation of spermathecal duct before entering ampulla, 
/ = funnel of sperm duct. 
ov = ovary. 
p — penis. 
•p.s = penial sac. 
r.)ii = retractor muscle (much exaggerated in the diagram). 
S2).d = sperm duct. 
sji.fi = spermiducal gland. 
S2).s = sperm sac. 
S2)t.2) = spermathecal pore. 
S2)t.(l = spermathecal duct. 
te = testis. 
Figs 
1. Section (diagrammatic) showing the position of the gonads, and the structure of 
the male genital apparatus. 
2. Diagrammatic representation of the spermathecae. 
3. 4, 5, and 6. Diagrams representing the relations of the penis to the atrial sac. 
3. Solid penis as in Astacopsidrilus and Gondwanaedrilus. 
4. Hollow penis as in Phreodrilns africamis. 
5. Hypothetical intermediate stage in which only half of the penis as represented in 
figs. 3 and 4 is free in the penial sac ; the other half represents the atrial sac 
of PJireodrilus heddardi and P. suhterraneiis. 
6. Atrial sac and penis of P. heddardi and P. snhterraneus. 
