NEWTON .IND HARRIS : OLIGOCENE AND EOCENE PULMONATA, 75 



Shell narrow, elongate, composed of eight whorls with rather com- 

 pressed sides ; volntions increasing gradually at first, afterwards more 

 rapidly ; spire moderately short and very acute ; body whorl extending 

 rather more than two-thirds the entire length of the shell, obtusely 

 angulated at the shoulder ; aperture narrowly ovate and contracted 

 anteriorly ; columella fold prominent, strongly twisted, nearly round, 

 and obscurely sulcated ; inner lip covered with a thin expansion ; 

 internal structure of test irregularly corrugated. Alt. 38 ; diam. 

 19 mm. 



This species differs from all other Tertiary forms of the same genus 

 by reason of its pronounced angularity at the shoulder, which, how- 

 ever, becomes more obtuse with age. The great length of the 

 aperture is also very characteristic. In some of its details it 

 approaches both Limncea fusifonmis, J. Sowerby, and Z. caudata, 

 Edwards, which occur on the same geological horizon. This species 

 is represented in the ^N^ational Collection by two specimens, the type 

 figured being rather smaller than the other, but in a better state 

 of preservation. 



Formation. — Oligocene (Headon Beds). Locality. — Headon Hill. 



PITHAEELLA, F. E. Edwards. 

 Geologist, 1860, pi. v. figs. 1-3, p. 210. 



Generic Characters. — "Shell sub-cylindrical; spire obtuse, more 

 or less produced ; aperture oval-oblong, rounded in front, narrowed 

 behind; columella straight, or very obliquely twisted, arched anteriorly; 

 outer lip simple, acute ; inner lip thickened." — Edwards. 



PiTHARELLA EicKMANi, F. E. Edwards. PI. VI. Figs. 7-9. 



Valuta, C. Rickman. — Geologist, 1860, p. 151. Pitharella Richnani, 

 F. E. Edwards. — Geologist, 1860 (reference as above). S. V. Wood. — 

 Mon. Pal. Soc. 1877, p. 339. E. B. :N"ewton.— Syst. List Edwards 

 Coll. 1891, p. 280. 



''Shell oval-oblong, smooth; spire sub- conical, short, varying in 

 height in different specimens ; whorls five or six, depressed on the 

 posterior margins, and obtusely angulated on the shoulders. The 

 sutural edge is slightly thickened, forming a narrow, upright, ribbon- 

 like band, pressed against the preceding whorl, and feebly crenulated 

 by the lines of growth ; in well-preserved specimens the margin 

 immediately in front of the sutural band presents two or three obscure 

 concentric furrows. The last whorl is somewhat attenuated towards 

 the base ; the aperture is entire, rounded in front, narrow behind, 

 and very long, nearly equalling four-fifths of the entire length of the 

 shell ; the columella is obscurely and very obliquely twisted, and 

 anteriorly is much curved ; the outer lip is slightly arched, simple, 

 and sharp on the edge ; the inner lip is posteriorly thickened and 

 narrow, anteriorly effuse, flattened, and reflexed, forming an angular 

 ridge on the columella, and confluent with the outer lip." — Edwards. 



Dimensions of the largest specimen figured. — Alt. 45 ; diam. 24 mm. 



