450 PHILOSOPHY OP ZOOLOGY. 



" On the 20th," he says, " the young were hatched, and the 

 shell completely formed.*" It is much more becoming in a 

 philosopher to observe how nature operates, than to pro- 

 nounce what she must do. 



Order I. TERRESTRIAL. 



The animals of this order reside constantly on the land. 

 When by accident they fall into the water, they appear to 

 be incapable of using their foot as a sucker or as a fin, and 

 die after a few writhings. The species in general prefer 

 moist places, and are seldom very active in dry weather. 

 After a shower they speedily leave their hiding places, and 

 at this time they may be readily collected. The eggs are 

 hatched on land 



1st Subdivision. 



Cloak and foot parallel, and containing the viscera be- 

 tween them. 



In this group are included those animals denominated 

 slugs in this country. They possess four retractile tenta- 

 cula, of unequal length. The eyes are two in number, in 

 the form of black points, seated at the tips of the posterior 

 tentacula. 



1st Tribe. 



Cloak with a shield. This shield is, in general, strength- 

 ened internally by a deposition of earthy matter, in the 

 form of grains, or a shelly plate. 



A. Shield anterior. In this group the shield is placed 

 nearer the head than the tail. It contains four genera, 

 two of which have compound tails, or furnished with pecu- 

 liar organs, while in the remaining genera the tails are sim- 

 ple. The mouth consists of lips, which are capable of small 

 extension, and above, the entrance is armed with a concave 



