CONOVULUS. 297 



respect to each other, and in the method, as the collective 

 value of the characteristic organs either of one or the other 

 preponderates; for instance, the Cyclostoma eleyans, a land 

 branchifer, falls into natural position with the marine Pectini- 

 branchiata. And though Carychium and Acme are Pulmoni- 

 fera, and the Pyramidellidcs Branchifera, still the peculiarity 

 of their organs and shells associates them nearly as closely 

 with the marine as with the terrestrial Mollusca. 



CONOVULUS, Lamarck. 



C. DENTICULATUS, Mont, et Auct. 

 C. denticulatus, Brit. Moll. iv. p. 194, pi. 125. f. 3. 



Animal inhabiting a spiral shell of 6^ volutions ; the first 

 very large and ventricose, comprising fths of the whole ; the 

 others are short, flat, and closely packed, with the apex as 

 much reflexed as in many of the Chemnitzia ; it is invested 

 with a lightish brown epidermis, which often forms, at the 

 upper part of the lower volutions, a row of minute, close-set, 

 hairy papillae, with a short filament proceeding from each ; 

 these are very caducous. 



It is curious that the reflexed apex, or the fold within the 

 aperture, invariably produces an animal with eyes immersed 

 either at the centre of the bases, or more usually at the 

 internal angles of the tentacula; for instance, this is seen in 

 Conovulus, Pedipes and Carychium, Tcrnatella, Chemnitzia 

 and Eulima and in the Limneadce that have a certain con- 

 nection with the Conovulidte, as most of them have more or 

 less developed folds on the columella, and show the same 

 tendency to a basal position of the eyes. 



The mantle is even with the shell, thick, and fleshy ; the 

 neck is very long, often far protruded, and forms beyond the 

 tentacula a very elongated muzzle, which expands into a large 

 subcircular, arcuated, bilobed emarginate disk, with the buccal 

 orifice in the centre quite beneath, and cloven vertically and 

 crosially : this is the head, which is always in advance of the 

 foot : there are no neck-lobes, but two very small suboval 

 head-lappets may be observed near the terminus. The tenta- 



