350^. H. ambigua Adams. f 



T. vix umbilicata, depresso-orbicularis, cornea; spira con- 

 vexa; sutura impressa; anfr. 6 convexi, ultiinus rotundatus; 

 apertura lunaris; perisl. tenue, acutum. (Rv.) — A single in- 

 dividual occurs, which is like H. similis , but smaller; with 

 the spire more elevated, the columella less oblique, and the 

 anterior part of the lip direclly transverse, with a smaller um- 

 bilicus. The suture is deeper than in H. similis or in H. ar- 

 horeoides, between which this shell is in most characters in- 

 termediate. Greatest breadth 0,46, least breadth 0,42, height 

 0,25 inch. (Ad.) 



Helix ambigua Adams Contrib. to Gonch. N. 3. p. 35. 

 — — Reeve Conch. ic. N. 320. t 63. 



Habitat in insula Jamaica. 



Nr 357 adde: Reeve N. 882. t. 139. Nr. 360 adde: Reeve N. 600. t. 107. 



365^. H. placentula (Zonites) Shuttleworth. -f- 



T. aperte umbilicata, depressissima, arctispira, nitidissima, 

 striis distantibus irregularibus impressis notata, cornea, dia- 

 phana, subtus concolor; anfr. 7 lentissime accrescenles, vix 

 convexiusculi, ultimus subtus convexus, ad umbilicum subex- 

 cavatus; apertura obliqua, lunaris; perist. simplex, acutum. 

 — Diam. maj. TVa, mi"- 6V4, alt. 3^4 "»•'. (^Sh.) 



Zonites Placentula Shuttleworth in Bern. Mittheil. 1852. Aug. 

 p. 194. 

 Habitat in Tennessee Americae septentrionalis (Rugel). 



Nr. 367 adde: Reeve N. 733. t. 122. Nr. 373 adde: Reeve N. 332. t. 65. 

 - 369 



372 



