PLATE II 



GASTROPODA 



i. Ampullaria canaliculata, Lamk. (from d'Orbigny): s\, siphon; o., 

 operculum. 



2. Natica Alderi, Forbes (from a drawing by Alder), showing the 

 extension of the fore-part of the foot so that it protects the aperture of 

 the mantle cavity while the animal is grouping in the silt after its prey. 



3. Aporrha'is pes-pelecani, Linn, (from a drawing by Alder). 



4. Valuta undulata, Lamk. (after Quoy and Gaimard). In this, as in 

 Figs, 6 and 8, the foot is flattened out to enable the animal to crawl 

 over soft mud, and even to swim with it. 



5. Pomatias elegans, Mull, (original by S. P. Woodward), in which 

 the foot is divided longitudinally, and the animal progresses by 

 advancing first one half and then the other. 



6. Buccinum iindatum, Linn., or Common Whelk (original by S. P. 

 Woodward). 



7. Vivipara vivipara, Linn, (original by S. P. Woodward). The 

 young shells are seen through the translucent shell of the parent. 



8. Dolium perdix, Linn, (from Quoy and Gaimard). The siphon is 

 carried recurved over the back of the shell, and the remarkable pro- 

 boscis is shown extended in front. 



9. Trivia Europaa, Mont, (after Forbes and Hanley). The extended 

 mantle meets over the back of the shell. The siphon rises up in front 

 between the tentacles. 



