HELIX. 91 



whorl, at a little distance behind the parietal tooth, (vol. 

 ill. p. 32). This lamina does not, however, distinguish it 

 from the allied species, H. microdonta. The variety is also 

 characterized by a less expansive umbilicus. It occurs in 

 vast numbers on the banks of Indian River, Florida. 



I am indebted to Mr. O. M. Dorman for fresh specimens 

 of the true cereolus, found by him near St. Augustine. I 

 have not received the species from any state but Florida, 

 though PfeifFer gives Georgia also as its habitat. 



Another variety is furnished with the alternating spots 

 which distinguish H. microdonta. 



HELIX MICRODONTA Deshayes. 



Plate LXXVIII. Figure 23. 



Testa discoidea, planulata, albo-grisea, flammulis obliquis fuscis sub- 

 rubescentibusve ornata ; superne spira depressissima, subtus profunde 

 lateque in arabitu umbilicata, tenuissime et regulariter striata ; apertura 

 obliqua, marginata, ovato-semilunari ; labio dente obliquo minimo proe- 

 dito. Diam. 10; alt. 4 mill. (Deshayes.) 



SYNONYMS AND REFERENCES 



Helix mhrodonta Deshayes, in Fer. Hist. i. p. 6, pi. Ixxii. fig. 13. 



Chemnitz, ed. 2, i. 380 (1846), pi. Ixvi. figs. 10-12, (1849). 



Pfeiffek, Mon. Hel. Viv. i. 409; iii. 262. 



Reeve, Con. Icon No. 705 (1852); No. 1040 (1853), unspotted 

 var. 

 Helix plana Dunker, Phil. Icon, i 3, p. 51, tab. iii. fig. 11. 



This shell was known to Dr. Binney by the numerous 

 specimens in his cabinet from Florida Keys. He did not, 

 however, recognize it as distinct. It is readily known by 

 the alternating blotches of white on the under surface of 

 the whorls, its heavier shell, less numerous whorls, and 

 the internal lamina described under cereolus. This lamina 

 and the white blotches are almost universally present. 

 Specimens are common in cabinets. I have it from Key 

 Biscayne, and many other Florida keys. Pfeiffer quotes 

 it from Bermuda and Texas, and Poey from Cuba. The 

 figure is copied from that of Deshayes. 



