274 FUNCTIONS AND INSTINCTS. 



them with the nerit, 1 the snail, 2 or the peri- 

 winkle, 3 that this umbo or knob is analogous to 

 the spiral part of those shells, as he will see upon 

 examining one of the bonnet-limpets, 4 in which 

 he will detect an incipient decurved spire ; pas- 

 sing from this by one of the chambered-limpets, 5 

 it will lead him to the neritidans, or top-shells, 

 from which the road is direct to the sea-ear ; a 

 and by another 7 he arrives almost immediately 

 at the periwinkles and snails. If he chance to 

 examine further between the limpets and the 

 whelks, 8 he will find another open shell, 9 which 

 forms the path to the latter genus. If once 

 more his eye happens to observe a shell almost 

 open 10 but with the sides a little turned in, he 

 will see still another road leading by the dippers 11 

 to the elegant tribe of cowries. 12 It is by this 

 road that Lamarck travels to them. Again, he 

 may perhaps be shewn, preserved in spirits, 

 an animal whose respiratory orifice is covered 

 by a round shield this is the sea-slug, 13 an 

 animal famous for Pliny's legend of its noxious 

 qualities, whose head resembles a hare, which 

 leads from the Patellidans towards the common 

 slug of our gardens. 14 To the bivalves there 



1 Nerita, Neritina, &c. 2 Helix. 



3 Turbo. 4 Pileopsis ungarica, &c. 



5 Crepidula. 6 Haliotis. 7 Calyptrcea. 



8 Buccinum. $ Concholepas peruviana. 



10 Bullaa. 11 Bulla. Cyprcea. 



13 Laplysia depilans. 14 Limax. 



