OF LAMARCK'S SYSTEM. 



piece, never spiral, always exterior • 1 . 



Shell exterior, covering : in one piece in the form of a shield, cap 

 sandal ; or in several imbricated pieces : imperfectly or not at 



spira 



, or) 

 all V 2. 



Shell partly or completely interior ; cavity simple or none ; only forming) ^ 



a spire when the whorls completely cover each other . J 



Shell exterior ; not capable of entirely containing the animal; the spire} ^ 

 imperfectly formed of two whorls J 



Mouth of the shell entire ; no notch or canal at the base 5. 



A channel more or less long at the base of the shell ; ) r n 



i. i- . 8. > o. Canalifer,e, 



outer hp not changing with age ) 



A channel more or less long at the base of the shell ; 



outer lip changing its form with age and having a 



sinus below J 



A short channel ascending towards the back, or an > g 



oblique notch sub-ascending at the base of the shell, j c ' ' 



No channel, a notch at the base of the mouth; folds j 



on the columella j 



No channel, the base of the mouth notched or efFu-l^Q 



sive; the whorls large, rolled round the axis j 



Shell channelled 

 or notched, or 

 effusive* at its 



I base* ........ 



7. Alat^. 



PfRPURIFERiE, 



Columella! - ^. 

 Involute. 



'ilTHOCER ACE.E, 



Multilocular, 

 with septa. 



Septa simple at 

 the edges, su- 

 | tures neither 

 i notched or un- 

 ! dulated on the 



Shell straight or almost straight ^ 



no spire j 



Shell partially spiral, last whorl 1 12< JjITlJ£)LACE ^ 



terminating in a straight line.. . j 

 Shell semi-discoid, spire eccentric 13. Cristace.e. 

 Shell globulous spheroidal or oval ;] 

 whorls of the spire enveloping, vl.4. 

 or cells united within a covering J 

 internal parti- ) i Shell discoid, spire central, cells \ 

 tion of the tes- | radiating from the centre to the>15. Radiate. 



taceous cover- 1 circumference j 



ing I Shell discoid, spire central, cells i 



in a spiral line, not extending f^g 

 from the centre to the circum-i 



fere nee ) 



Septa notched at the edges, united against the inter- ^ 

 nal partition of the testaceous covering and arti* jj 

 culated in sinuated sutures notched like parsley j 

 leaves .1 



Unilocular, univalve, involute; spire entering the mouth or tendingl^g 

 towards it , , j 



ALTILACE.E. 



Ammonace.e, 



* F. Note, p. 27. 



