TRUNCATELLA. 185 



A figure of the animal as it appears while in motion is 

 given on pi. 75, fig. 11, taken from Adams's Genera of 

 Recent Mollusca. It represents a species not found in 

 our country. 



The animal walks by contracting the space between its 

 lips and foot, like the geometric caterpillars. 



Remarks. This genus has been but little understood by 

 authors until the most recent investigations have proved 

 it to belong to the same group as Helicina, Cyclostoma, &c. 

 It has formerly been referred to the following genera : 

 Truncatula, Fidelis, Choristoma, Erpetometra, Helix, Turbo, 

 Cyclostoma, Acmea, Paludina, Pyramidis, Rissoa, and 

 Turritella. A full description of it will be found in the 

 works of Pfeiffer referred to. 



At first sight it seems almost impossible to admit of 

 more than one species among the shells I have received 

 from Florida. However well marked may be some indi- 

 viduals, when separately compared, there seem to be 

 many others forming a chain of connection between them. 

 I have, however, sent to Messrs. PfeifFer and Poey our 

 Florida specimens, and have received from them the de- 

 cisions regarding their identity which I give below. 



In all cases I have given Pfeiffer's Latin description of 

 the species, and the figure of it to which he refers. 



TRUNCATELLA CARIB^ENSIS SOWERBY. 

 PLATE LXXV. FIGURES 2, 4. 



T. subrirnata, subcylindrica, parum attenuata, solidula, rubella, suc- 

 cinea vel flavida, subtiliter costulata ; costulis subrectis, saepe in medio 

 anfractuum evanescentibus ; sutura Isevis ; anfr. superst. 3-4, sensim ao 

 orescentes, parum convexi, ultimus saepe lievigatus, basi breviter carinato- 

 cristatus; apertura subverdcalis, ovali-elliptiea, superne angulata ; perist. 

 continuum, rectum, ad anfractum penultimum et in angulo insertiouis 

 incrassatum. ( Pfr.) 



SYNONYMS AND REFERENCES. 



Truncatella Caribxensis SCMVERBY, MSS. 



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