136 THE GASTROPODA 
between the foot and anus, in front of the pallial cavity, ef 
Helix, Bithynia, Vermetus, the Rachiglossa, and nearly all the marine 
Gastropoda, including the “ Pteropoda,” Heteropoda, and Nudi- 
3 ° 
O 03%0 
oe PRP - 
A 
Fic. 116, 
Larvae of Eolis (Galvina) exiqgua. A, on the second 
day, left-side view. I, radula; II, foot; III, otocyst ; 
IV, operculum ; V, shell. 2B, on the third day, after 
the loss of the shell, dorsal aspect. I, eye; II, left 
liver lobe; III, foot; IV, anus; V, octocyst; V1, 
radula. (After Schultze.) B 
branchia. This sinus is displaced, together with the pallial aper- 
ture, along the right side towards the neck (Fig. 114, II), and 
finally is partly contained in the pallial cavity. In the Basom- 
matophora there is a velar dorsal sinus, and in the Stylommatophora, 
Helix aspersa, emoryo of the tenth day, right-side view. coq, shell; o.ca.c, external opening 
of the cerebral cavity ; p, foot; pa, mantle; po, contractile vesicle or podocyst; te’, the true 
tentacles ; te’”’, labial palp ; vit, vitellus. 
Arion, Limax, Clausilia, Helix, etc., but not in Succinea, there is a 
caudal vesicle, known as the pedal sinus or podocyst (Fig. 117, po). 
The larval kidneys are paired and generally symmetrical organs 
situated at the anterior end of the body, immediately behind the 
velum or apical area. In the marine Streptoneura they are caducous 
ectodermic projections, in which the products of excretion are 
