274 TRANSACTIONS OF THE WAGNER FREE 



its posterior angle sharp ; pillar thin, passing into the peristome almost in- 

 sensibly ; canal obsolete, a thin callus sometimes spread over the body. Lon. 

 of shell 5.75 ; max. lat. 2.5 mm. 



This species, though larger and more sharply sculptured, is obviously 

 the precursor of B. alternatum Say of the Post- Pliocene and recent fauna. 



Bittium podagrmum n. s. 

 Plate 21, figure 12. 



Pliocene of the Caloosahatchie and Shell Creek, Florida, Dall and 

 Willcox. 



Shell small, swollen, with three small, inflated, smooth and polished nuclear 

 and four rapidly increasing subsequent, reticulated whorls, the last third of the 

 last "of which is contracted so as to be smaller than the antecedent coil of the 

 shell ; spiral sculpture of, on the body-whorl, about four obscure grooves, 

 separating wider, somewhat rounded, flatfish interspaces, and cutting more or 

 less distinctly the numerous flattened, straight riblets which cross from 

 suture to suture, sometimes nodulated at the intersections, but more com- 

 monly flattened ; upper whorls of the spire flattened, the penultimate whorl 

 swollen, the last whorl contracted in its later half, which is destitute of riblets 

 and shows an obscure varix ; base spirally sulcate or sometimes nearly 

 smooth ; aperture ovate, oblique, the inner lip raised and nearly continuous 

 with the peristome; canal practically obsolete ; pillar not distinct from the 

 raised labrum ; outer lip thin, simple ; throat non-lirate ; suture very distinct. 

 Lon. of shell 4.75 ; max. lat. 2.75 mm. 



This curious little species varies in obesity, but always has a swollen 

 look. It would probably be referable to Aneiirychilus, if that be regarded 

 as a section of Bitthim. 



Bittium (Diastoma ?) varium Pfeiffer. 



Ceriikum varium Pfr,, Arch. f. Naturg. 1840, p. 256, No. 139. 



CerUhium gibberuhim C. B. Adams, Proc. Bost. Soc. Nat. Hist. 1845, p. 5 ; Sby., Thes., p. 



876, No. iiS, figs. 2IO, 211. 

 Bittium varimn Morch, Mai. Blatt. x.xiii. p. 96, 1876; Dall, Bull. U. S. Nat. Mus. No. 37, 



p. 140, 18S9. 



Pliocene of the Caloosahatchie and Shell Creek, Florida, Dall and 

 Willcox; Post-Pliocene of North Beach, Florida, Dall. Living from Chesa- 

 peake Bay to St. Thomas, W. Indies, Dall, Krebs, Adams, etc. 



This species is frequently confounded with B. alternatum (or nigrum). 

 Its obliquely set mouth, angulated at both ends, especially behind, has sug- 

 gested that it may properly be referred to Diastoma, but this state of the 

 shell is confined to fully grown adult specimens ; the young show nothing of 

 the posterior sinus. 



