Dentition of Pulmonale Mollusks. 127 



Part ula. 



Jaw as in Cylindrella. PI. XV, fig. 0, 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 Helicidm, 

 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 citrina, 11 in planilabrum, 10 in abbreviata and 

 amanda, 8 in umbilicata, bilineata and vir ginea; 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 lirata by 

 Heynemann, Mai. Blatt., 1867, PI. I, figs. 1— la. 



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. 



, umbilicata, Pease. dentifera, Pease. 



bilineata, Pease. crassilabris, Pease. 

 amanda, " (PI. XI, fig. L) Hebe, Pfr. 



virginea, Pease. protea, Pease. 



gracilis, Pease. globosa, Pease. 



turgida, Pease. approximata, Pease. 



rosea, Brod. faba, Martyn. 

 formosa, Pease. 



ELASMOGNATHA. 



Jaw with accessory plate to its upper margin. 



Omalonyx. 



Omalonyx felina, Gnppy. Demarara. Mr. J. S. Gibbons. 



