65a. 
65b. 
66a, 
66b. 
67a. 
67b. 
68a. 
68b, 
69a. 
69b. 
70a. 
70b. 
oleate 
Tb: 
iaaas 
Mee 
Toa 
73b. 
Ligon 
Aperture more than 1/2 the 

height of thetsherliisec clelevele ele re etetercnet cele sie s siete oe OSSarlalonula 
Aperture less than 1/2 the 
height ofthe Sheu aes rachel elerctaraters ....-.. Fossaria truncatula 
Base of columella truncate; 
shell imiperforateves ej. isc ielelelelaicle oletelerlie slot eieler eucionenel ate te telers SS co OT 
Base of columella straight, not 
truncate; shell perforate ss se cies ola cheleke a) or edelancl ovolc) ciel lente eaeter ewan re wen One 
Shell small, adults(with 5-6 whorls) 
less than 6 mm. (1/4 inch)long; very 
glossy; shell surface smooth or only 
VELY weakly *StNTAtew es sc. sols OO Oooo ROO OUso Soon OL 
Shell medium, adults more than 
6 mm. (1/4 inch)long; moderately 
clossy; shell surfaceistniate oreo ssfer sieke tote oe eee ss - DUDULIna Octona 
Base of columella abruptly truncate; 
no callus on parietal wall; whorls 
nearly flat-sided; shell surface 
weakly Striaters.: cciiers selene oeerets wesc seieis se GeCiuoides, acicullial 
Base of columella mabdeencely 
truncate; callus present on parietal 
wall; whorls convex; shell surface 
SIMOOEtNS se cle) « SES OOO CIID SIO wai setlede) sieieners . Cecilioides aperta 
Shell surface Seal peaced with 
raised axial ribs; aperture length 
less than 1/4 the shell height..... CODD DOO -.-.--Lamellaxis micra 
Shell surface without raised axial 
ribs; aperture length more than 
A> themshelll phe i otiters tee atevoieleletet et tenater oer aie toler an SooUEeScooredcdg VU 
Sutures distinctly crenulate (that 
is, undulated or scalloped)! 4.22) scl cee eee see sree te ODeas pyapuli 
Sutures straight or only very 
slightly crenuliate’s >... HOS BO Sac nso oOCOcOOKKb Ooo G. Ml 
Upper lip strongly pemrierent ap 
thessuturelerie. cis ce ala lalol eve lelelielc! cleictelelelevetalelehohelelete) te OD ea S mone mann 
Upper lip straight or sally moderately 
retracted at the sutures. 5 22/1 sec erenoncvoleters esi eteleoiciere reener ener nemememen mace 
Shell heavily striate; not glossy............... Lamellaxis gracilis 
Shell moderately to weakly 
Striatess Glossy co 27s 8. s cle oe oe ctene ciietiel stoner evel orekehn len Neher el tenet ce wememene tre aves 
Shell very glossy; weakly striate.......... -Lamellaxis mauritianus 
Shell moderately glossy; 
moderately ‘striate’. 2% 2 cco « cic cute ee icine oak LL axl Sac anal laraus 
