136 PNEUMONOBRANCHIATA. 



The shell varies greatly : — 



1. In size. 



2. In the intensity of the bands. 



3. In the ventricoseness, and 



4. In the height of the spire. 



Monstrosities are sometimes found with the spire 

 depressed, when it is Helix pomana of Muller; and 

 others with the spire produced and conical, when it is 

 H. scalaris of the same author. 



5. It is sometimes reversed, and very rarely the 

 whorls are separated one from the other like a cor- 

 nucopia. (See Feruss. Hist. t. 21. f. 7, 8, 9.) 



The eggs are globular, covered with a white, opake 

 coriaceous skin, and are about two and a half lines in 

 diameter. They are figured by PfeifFer (t .7. f. 2.), who 

 has given a most complete and interesting description 

 of all the changes which the egg undergoes during its 

 hatching, in the first plate of the third part of his 

 work. 



Lister {Tab. Anat. t. 1.), Harderus {Basil, 

 1676.), Swammerdam {B.Nat, t. 4.f. 1.4.) Gas- 

 pard {Ann. Sci. Nat. §• Zool. Journal, i. 93.), and 

 Cuvier (Mem. Moll.), have given accounts of the 

 anatomy of this species of snail. 



From the time of the Romans, who fattened them 

 as an article of food, they have been eaten by various 

 European nations, dressed in various ways. Petronius 

 Arbiter twice mentions them as served up at the feast 

 of Trimalchio (Nero), first fried, and again grilled on 

 a silver gridiron. 



At one period it seems that they were admitted at 

 our own tables ; as Lister, in his Hist. Anim. Angl. p. 

 111., tells us the manner in which they were cooked 



