62 PLEKOCHEILUS. 



Family BULIMULID^E. 



=Bulimulidce-\- Orthalicidce of authors. 



Shell varying from well developed, oblong, ovate, conic or cylin- 

 drical, and capable of containing the retracted soft parts, to Succinea- 

 like, or depressed, few whorled, and incapable of containing the soft 

 parts. 



External characters of animal as in ffelicidce. Genitalia rather 

 simple, the penis with or without a flagellum or an accessory gland 

 or " appendix." Jaw composed of vertical or oblique imbricating 

 plates, sometimes forming a triangular median piece composed of 

 one or several plates, or sometimes by thickening of the plates hav- 

 ing an odontognathous appearance. Radula fundamentally as in 

 Helicidce, but variously modified. 



Habits arboreal or terrestrial. Genera about fifteen, inhabiting 

 tropical and subtropical America, and in the Old World extending 

 from Tasmania and Australia to China, and eastward in Polynesia 

 to the Society Islands. 



An extensive family, comprising the dominant groups of South 

 American land snails, and abundantly represented in the Orient by 

 Placostylus, Partula, Amphidromus, etc. As only a portion of the 

 genera will be discussed in this volume, the consideration of the 

 geographic and geological distribution and the anatomy, as well as 

 synoptical keys to the genera and subgenera, will be reserved for the 

 Introduction to a later volume. 



The several genera will now be monographed, beginning with 

 those South American groups having greatest similarity in shell 

 characters to the Bulimoid Helicidce. This proximity must be 

 clearly understood to be a grouping of convenience only, indicative 

 of no natural affinity. 



* * 



Genus PLEKOCHEILUS Guilding, 1828. 



Plekocheilus GUILDING, Zoological Journal, iii, p. 532, type P. 

 undulatusauris sileni. Caprella Guilding olim, not Lamarck. 

 Bulimus, in part, of previous authors.-}- Eurytus ALBERS, Die Hel., 

 p. 169, 1850. 



For anatomy see SCHAKO, Festschrift zur Feier des 100-jahrigen 

 Bestehens der Gesell. Naturforsch. Freunde zu Berlin, 1873, p. 173 

 (jaw and teeth of blainvilleanus). BINNEY, Ann. N. Y. Acad. Sci., 



