THE GASTROPODA 107 
genus the appendage is to the left of the pallial aperture). In 
Planorbis corneus (Fig. 89, g) there is a single respiratory lobe, with 
a richly vascularised surface, and in Ancylus there is a similar 
| rd 
odin V 
Fic, 8s. 
Diagram of a sagittal section of Patella vulgata. br.a, branchial afferent vessel (artery) ; 
br.v, branchial efferent vessel (vein); b.v, blood-vessel ; ec, muscular substance forming the root 
of the foot ; cor, heart within the pericardium ; e, mantle-skirt ; f, papilla of the larger kidney ; 
g, anus ; 7, smaller kidney ; k, larger kidney ; 1, pericardium ; 7, liver; 0, mouth ; od.m, muscles 
and cartilage of the odontophore; p, snout; g, intestine in transverse section; 7, radular or 
lingual sac ; rd, radula; s, lamellated stomach ; ¢t, salivary gland; u, duct of same; 7, buecal 
cavity; w, gonad. (After Lankester.) 
structure, but the lung has disappeared. In Lulinus, including 
the sub-genera Jstdora, Pulmobranchia, etc., and in Miratesta there 
is a folded branchia. In Siphonarw the long plicated branchia 
which extends across the interior of the roof of the pulmonary 
Fic. 89. 
Planorbis corneus, removed from the shell; anterior view. «@, anus; f/f, foot; g, gill; k.o, 
renal aperture; m, mouth; os, osphradium; pu, mantle; pn, pneumostome; s/, pulmonary 
siphon. 
cavity, between the kidney and the rectum, is of the same 
character. This branchia is situated more posteriorly and to the 
right than the ctenidium of monobranchiate Gastropods (Fig. 174). 
The diverse characters of the respiratory apparatus of Gastropoda 
may be advantageously summed up in the following table :— 
