THE JAW AND LINGUAL MEMBRANE. 51 



BIBLIOGRAPHY. 



The principal works on lingual dentition referred to are : 



LEIDY in Binney's Terrestrial Air-Breathing Mollusks of the United 

 States. Boston, 1851, Little & Brown. The wood-cuts of lingual mem- 

 branes are misplaced in the text. See the list, Vol. II. p. 358. 



BINNEY and BLAND. Land and Fresh- Water Shells of North America. 

 Part I. Smithsonian Miscellaneous Contributions. Washington, 1869. 



MORSE in Journal of the Portland Society of Natural History, 1864. 



MOQUIN-TANDON. Histoire Naturelle des Mollusques Terrestres et 

 Fluviatiles de la France. Paris, 1855. 



FISCHER et CROSSE. Etudes sur les Mollusques Terrestres et Fluvia- 

 tiles du Mexique et 1'Amerique Centrale. Paris, 1874. 



LEHMANN. Die lebenden Schnecken und Muscheln der Umgegend 

 Stettins und in Pommern. Cassel, 1873. 



GOLDFUSS. Verzeichuiss der bis jetzt in der Rheinprovinz und West- 

 phalen beobachteten Land- und Wasser-Mollusken, nebst kurzen Be- 

 merkungen iiber deren Zungen, Kiefer, und Liebespfeile. Von Ver- 

 bandlungen des natnrhistorischen Vereins der preussischen Rheinlande 

 und Westphalens. 13 Jahrgang. Bonn, 1856. 



SEMPER. Landmollusken. Reisen im Archipel der Philippineu. 

 Wiesbaden, 1873. 



HEYNEMANN. Einige Mittheilungen viber Schneckenzungen, mit be- 

 sonderer Beachtung der Gattung Li max. Von Malako-zob'logische Blat- 

 ter, X. 1862. 



VON MARTENS. Die Heliceen von JOH. CHRIST. ALBERS. Zweite 

 Ausgabe. Leipzig, 1860. 



These are the principal works referred to. The references to shorter 

 papers in various periodicals will easily be understood. 



ON THE ILLUSTRATIONS OF DENTITION. 



I endeavored in the paper already referred to, and in my subsequent 

 papers, to give a good view of the central, lateral, and marginal teeth 

 of each species, with the transition teeth of many of the species. The 

 portion of the membrane chosen is different in the various species of 

 each genus or subgenus, in order that the variations in the form and de- 

 velopment of cusps and cutting points may be shown. Thus in some 

 figures I have selected the part of the membrane where the marginal 

 teeth have a very blunt cusp, while in others they are shown much 



