\ 
Dentition of Pulmonate Mollusks. 127 
Partula. 
Jaw as in Oylindrella. Pl. XV, fig. O, represents that of an 
undetermined species; there are over 60 ribs on that of P. vir- 
ginea. 
Lingual membrane broad; (that of amanda is figured on 
Pl. XI, fig. L) the central tooth is as common in the Helicide, 
with subobsolete side cusps, but side cutting points; the laterals 
are longer and broader than the central, with a side cusp and 
cutting point; the marginals have a long, narrow, quadrangular 
base of attachment, curving outward, extending beyond the re- 
flection above ; reflection small, with a highly developed cutting 
point, obliquely and bluntly tricuspid on its outer edge, the in- 
ner division the largest; the number of perfect laterals varies 
somewhat, 7 in cttrina, 11 in planilabrum, 10 in abbreviata and 
amanda, 8 in umbilicata, bilineata and virginea ; 5 in gracilis ; 
there were 120 marginals in virginea ; the number varies in the 
different species, but they are always numerous; the dentition 
of all examined by me agrees with the figure of that of dérata by 
Heynemann, Mal. Blatt., 1867, Pl. I, figs. 1—1la. 
The species were determined by Mr. Garrett. I examined :— 
P. fusca, Pease. lugubris, Pease. 
citrina, Pease. varia, Brod. 
planilabrum, Pease. compacta, Pease. 
abbreviata, Pease. Garretti, Pease. 
aumobilicata, Pease. dentifera, Pease. 
bilineata, Pease. crassilabris, Pease. 
mimo, °° (Tell, 201, atkex, 1D) Hebe, Pfr. 
virgined, Pease. protea, Pease. 
gracilis, Pease. globosa, Pease. 
turgida, Pease. approxtmata, Pease. 
rosea, Brod. faba, Martyn. 
formosa, Pease. 
ELASMOGNATHA. 
Jaw with accessory plate to its upper margin. 
Omalonyx. 
Omalonyx felina, Guppy. Demarara. Mr. J. 8. Gibbons. 
