242 E. A. ANDREWS 
ments of these bases seem to adjust the papillae so that they fit 
accurately into the orifices of the first stylets (figs. 30, 31) and by 
that means the sperm discharged from each papilla is passed into 
the cavity of the stylet. 
The papilla (P. fig. 1) is on the under side of the large first seg- 
ment of the leg and projects downward and toward the median 
plane; but its tip turns away from the middle line of the body. 
The papilla is a cone with bent apex. It is translucent and dis- 
tended with colorless blood. When directly injured, or upon les- 
sening of the blood pressure from injury elsewhere, the papilla 
collapses, being but a thin uncalcified protrusion of the skin, kept 
turgid, or erected, by blood pressure. Within the papilla one can 
see a large central tube passing toward the tip and also chalky 
white masses suspended between the central tube and the thin 
outer walls. 
On the shell at the base of the papilla there is, anteriorly, a 
single row of very long setae (fig.1 ) that form a sort of protective 
screen over the anterior face of the papilla. 
Sections show that the papilla is a continuation of the deferent 
duct, blood cavity and skin, so constructed that the bent, conical 
apex, with its soft walls can be adjusted to the hard opening of 
the stylet so as to fit hermetically, as a tense rubber bag might. 
Moreover the bent tip can be opened to discharge the sperm, 
when special muscles remove the obstructing valve that holds the 
tube closed. 
A lengthwise section through this delicate papilla (fig. 2) shows 
that the central tube is a direct continuation of the deferent duct 
that leads the sperm from the testes to the tip of the papilla. 
Between this duct and the outer cuticle there is a large space 
full of blood, traversed by little connective tissue and in it are the 
white bodies just mentioned, now seen to be small tubular glands, 
opening into the central duct. The central duct presents two 
strikingly distinct parts; the one continued from within the leg 
has the thick muscular wall and peculiar secreting lining of the 
deferent ducts, the other is lined by the thin cuticle inflected at 
the orifice at the tip of the papilla, and lacks muscle. In place 
of muscle the wall has only epidermis, which extends irregularly 
