67 
PLATE II. 
Fig. 20. Another section through the radular sac. 
ep. epithelium continuous with that of the pharynx. 
R,R’. the radula (which is bent backwards) twice cut, directly 
applied on this epithelium. 
T. tongue-like prominence of the muscles in this region. 
The cells dispersed between the muscular tissue which might 
be compared to the lingual cartilage are not represented in 
this section. 
Fig. 21. A section closely behind that from which fig. 19 was taken. 
un en En | continuous with that of the pharynx. 
ep. the epithelium. | 
R. oblique section of the radula. 
b. the basal membrane, secreted by the underlying epithelium. 
t. the teeth formed by the epithelium opposite. 
s and s’. the ducts leading into the salivary glands and opening 
anteriorly into the pharynx by the common opening r (fig. 16). 
fe) 
Q 
g.22. Schematie section through the foot and right salivary gland (illustrat- 
ing the connection between the two following figures). 
B, F and vs, as in fig. 12. 
I. integament. 
s. salivary gland. 
N. pedal nerve. 
fg. foot-gland. 
Fig. 23. Transverse section through one of the salivary glands and the ad- 
joining tissues. 
s. the interior cavity of the salivary gland and the glandular 
epithelium. 
m. the muscular tunie of the salivary gland. 
sl. the lacuna in which it is enclosed. 
bc. blood-corpuscles in this lacuna. 
ie. the folds of the intestinal epithelium. 
C. eonnective tissue. 
L. another blood-lacuna. 
lf. bundles of transverse muscular fibres. 
lm. ventral longitudinal muscles. 
cm. circular muscular layer. 
ei. cellular matrix of the integument. 
I, N and B, as in fig. 22. 
Fig. 24. Transverse section through the foot region. 
