246 



1429. Zelandiae, Gray. 1434. Zollingeri, Pfr. 



1430. Zelobori, Pfr. 1435. zonalis, Per. 



1431. Zeus, Jonas. 1436. zonaria, Linn. 



1432. Ziegleii, Schmidt. 1437. zonata, Studer. 



1433. zodiaca, Mr. 



1438. zonifera, Sow. 



1439. Zonites, P/r. 



1440. zonulata, Mr. 



1441. zosterophora, Pfr. 



Figures. 



Helix Listeri. PI. 21. Pig. 119. Shell, showing the orbicularly de- 

 pressed form, separated by Lamarck as Carocolla. 



Helix Luzonica. PI. 21. Kg. 122. Shell, showing its globose form 

 and reflected lip. 



Genus 9. ANASTOMA, Fischer. 



Animal ; similar to that of Helix. 



Shell; orbicular, globosclg lens-shaped ; the last whorl suddenly 

 turned upwards on a plane with the spire ; aperture semicir- 

 cular, furnished with Jive strong plait-like teeth, of which two 

 are on the body whorl ; outer lip thickened and reflected. 



In Brazil there exists a curious form of snail, of which two species ap- 

 peared fifty years ago in the works of Perussac and Lamarck, one being 

 already known to Linnseus ; yet, notwithstanding the researches of recent 

 travellers, no other species has been discovered. The peculiarity of this 

 form consists in the singular manner in which the latter half of the last 

 whorl is suddenly turned upwards, so as to bring the aperture on a plane 

 with the spire. Up to this period, the position of the shell on the living 

 snail would be, as in all other genera, with the apex uppermost ; but in 

 Anostoma the animal, on approaching maturity, so abruptly alters the coil 

 of the last whorl, as to turn the shell completely over, with the apex down- 

 wards. Both species are constant in their manner of growth, and are not 

 uncommon. 



Species. 

 1. ringens (Helix), Linn. 2. globulosum, Linn. 



J Figure. 



Anastoma ringens. PI. 21. Pig. 117. Shell, showing its semilunar 



