163 



48. Fusus. — A subfusiform univalve ; ventricose in the 

 middle or lower part, but with no varices ; the spine longish ; 

 the base channelled ; columella generally smooth ; and lip 

 entire. Recent and fossil. — PI. iv. fig. 23. 



49. Pyrula. — A somewhat pyriforra univalve, without 

 varices ; the spire short ; the base channelled and caudated ; 

 the columella smooth, and the lip entire. Recent and 

 fossil. — PI. iv. fig. 24. 



50 Pleurotoma, — A turriculated and subfusiform uni- 

 valve ; the lower part of the opening channelled ; a notch in 

 the upper part of the right lip. Recent and fossil. — 

 PL iv. fig. 25. 



51. Clavatula. — A subturriculated univalve, the opening 

 terminating by a short channel or notch ; a sinus in the 

 upper part of the right lip. Recent. — PI. iv. fig: 26. 



.'')2. Cerithium. — A turriculated univalve, the opening 

 oblique, terminating at the base by a truncated or recurved 

 canal, and upwards in a groove more or less distinct. Re- 

 cent and fossil. — PL iv. fig. 27. 



53. Melania, — A turriculated univalve, the opening oval 

 or oblong ; the inner lip spread out at the base of the 

 columella, which is smooth. Recent and fossil. — PL v. 

 fig. 1. 



54. Turritella. — A turriculated univalve ; the opening 

 roundish ; the margin disjoined in the upper part ; a sinus 

 in the right lip. Recent and fossil. — PL v. fig. 2. 



55. Pyramidella. — A turriculated univalve ; the opening 

 entire and semi-oval ; the columella projecting, furnished 

 with three transverse plaits, and perforated at its base. 

 Recent.— PL v. fig. 3. 



56. Auricula, — An oval or oblong univalve, with a 

 raised spire ; the aperture oblong, entire, and contracted 

 above ; the lips united ; the columella with plaits inde- 

 pendent of the decurrence of the outer lip. Recent and 

 fossil. — PL V. fig. 4. 



