OF LAMARCK’S SYSTEM. 
piece, never spiral, always exterior........+- cesses eee eneees aealeve efecto ip 
Shell exterior, covering: in one piece in the form of a shield, cap, or 
sandal; or in several imbricated pieces : imperfectly or not at all> 2. 
Shell partly or completely interior ; cavity simple or none; only forming) 3 
Shell exterior ; not capable of entirely containing the animal; the spire( 4 
imperfectly formed of two whorls............... SiS CAoonDnS dOoue 
Mouth of the shell entire ; no notch or canal at the base.............. iy 
A channel more or less long at the base of the shell ; ) Go Gina 
outer lip not changing with age................. 7 PEER 
A channel more or less long at the base of the shell; % 
outer lip changing its form with age and havinga} 7. Avatz. 
Shell channelled sinus below.... ie of 
ea ETI, 
seep ats A short channel ascending towards the back, or nt Cy ee ee 
Pasc oblique notch sub-ascending at the base of the shell. f ~° ; 
+ ee eee y No channel, a notch at the base of the mouth; folds) 9: Gos 
onthe columiellays 3:4: tejsiooieepotevrd betes Sepatelaseperos a es 2 ee 
No channel, the base of the mouth notched or effu- 40” Tee 
sive; the whorls large, rolled round the axis...... \ eh Seer Ss 
Shell straight or almost straight ; 
no spire . Sic Uo Uo COBOOpOAE ce do Maa. Onrnocenaces, 
Shell partially spiral, last whorl 
Multilocular, §Septa simple at fevininatinp ie straight line... \42, DiMCOLACEm. 
with septa, ..4 the edges, su-} Shell semi-discoid, spire eccentric 13, Cristacex, 
tures neither } Shell globulous spheroidal or oval ; 
notched or un-} whorls of the spire enveloping, 514. 
dulated on the or cells united within a covering 
internal parti- | Shell discoid, spire central, cells 
tion of the tes- | radiating from the centre to the $45. Ravrarez. 
taceous cover-§ circumference................ 
SHEE cD BBOIUO Shell discoid, spire central, cells 
in a spiral line, not extending 6. N 
from the centre to the circum-{—-* -\AUTUACE®. 
RELEMC Este Nensyatels noc) ote cutie oleh <rars : 
Septa notched at the edges, united against the inter- 
nal partition of the testaceous covering and ae A 
culated in sinuated sutures notched like parsley; /* “™MONACE®. 
TO@AWENES 32 271:5)210 o1<iopeleeate SAH EOUeG CORE Serer oh: aboae 
Jnilocular, univalve, involute; spire entering the mouth or pendant 18 
FOWVATOS Tease oi), </ols''« pia aie tcxal o/s area sanbo man topes dpoeaane A ae 
* V. Note, p. 27. 
