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CHAPTER XLI. 



CONOVULUS. CARYCHIUM.— CYCLOSTOMA. ACME. 



AUBICULIDJE AND CYCLOSTOMID JE. 



The Auriculidm are air-breathing molluscs,, with volute- 

 shaped shells, which frequent marshy places or sea-beaches, 

 within reach of the salt spray. 



CoNOVULUS has an oval or rather conical shell, with small 

 spire, and the aperture toothed. It has triangular tentacula, 

 with eyes at their bases. 



C, bidentatus is white, with the crawling disc of the foot di- 

 vided across the middle. This makes the method of 

 crawling very peculiar. The front part, with the head 

 and neck, moves forwards, and, taking it^ hold, waits 

 in a fixed position until the other part comes up to 

 it with the shell; then another advance of the front, 

 and so on ; making the march tedious. The shell is 

 white, and has two folds on the pillar. 



