188 ACICULACEA. 



in Florida, and having been referred to Pfeiffer for identi- 

 fication, was returned with the name of subcylindrica. 



Its accidental introduction into England accounts for 

 its presence in the English works above referred to. 



The base is not furnished with the prominent ridge or 

 carina. 



TRUNCATELLA BILABIATA PFEIFFER. 

 PLATE LXXV. FIGURES 3, 7. 



T. subrimata, cylindracea, gracilis, solida, opaca, fusca, costulata ; costis 

 subarcuatis, elevatis, obtusis, interstitia sequantibus ; sutura profunda, 

 simplex ; anfr. superst. 4|-5 convexi, ultimus vix longior, basi subcom- 

 pressus, callosus ; apertura verticalis, ovalis, superne vix angulata ; perist. 

 duplex ; externuoi album, callosuni, patens, in cristam basaleni transiens, 

 internuin continuum, breviter porrectum. 



SYNONYMS AND REFERENCES. 



Truncatella Ulabiata PFEIFFER in Wiegra. Arch. 1840, i. 253; in Zeit. f. Mai. 1846, 



p. 187; Mon. Auric. Viv. 192; Mon. Pneum. Viv. ii. 8. 

 CHEMNITZ, ed. 2, p. 7, pi. 1, figs. 27-31. 



DESCRIPTION. 



Animal not observed. 



Shell subperforated or grooved, cylindrical, elegant, solid, 

 opaque, brownish ; ribs subarcuate, elevated, obtuse, at 

 equal distances ; suture deep and simple ; remaining 

 whorls 4| to 5, convex, the last scarcely longer than the 

 others, heavy and subcompressed at base ; aperture verti- 

 cal, oval, scarcely angular above ; peristome double, the 

 outer one white, heavy, and terminating in the basal ridge 

 or carina, the inner one continuous. 



Length 5g, breadth If, length of aperture 1| millimetres. 



Geographical Distribution. Found with the preceding 

 species ; also in Cuba (Pfeiffer), and on Carmen, an island 

 of the Gulf of Mexico (Kiister). 



Remarks. The duplicated peristome and highly devel- 



