114 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 7, 



Four folds in tlie interior reducing the hollow of the whorl to a very 

 narrow complicated passage ; viz. two folds on the columella, of which 

 the upper is thin and very small, the lower larger, with a wide base 

 which rapidly decreases to a thin edge and is again thickened at the 

 extremity ; one large fold on the top of the whorl with a wide base, 

 curving outwards and thickened at its extreme edge, and one fold 

 on the outer lip thickened at its edge. Besides these four folds there 

 is a callosity at the top of the whorl near the outer lip and another at 

 the base of the whorl. 



Sutural angle between 95° and 100°. Basal angle 1 10°. 



Rare in the hippurite limestone near Lisbon. 



Closely allied to N. Olisiponensls, this species may be recognised 

 by its cylindrical form, deep sutural depression, and by a more com- 

 phcated internal structure. 



I have named this shell after the Baron d'Eschwege, the first geo- 

 logist who seriously attempted to work out the series of Portuguese 

 formations, and to whose kindness I have been largely indebted for 

 assistance and information during my visits to Portugal. 



Plate XIII. fig. 2 a. Exterior. 



Fig. 2 b. Section of the same specimen. 



Nerin^a Olisiponensis, n. s. 



Shell turreted, shghtly conical, smooth ; spire increasing slowly ; 

 spiral angle 10° in the young, 5° in the old shell. Whorls very 

 numerous, smooth, with straight sides and nearly flat below, separated 

 by a well-marked suture. Columella solid, small. Four folds in the 

 interior, which reduce the hollow to very narrow dimensions of a most 

 complicated form, viz. two folds on the columella, of which the upper 

 is small and sharp, the lower prominent and thickened at the extre- 

 mity ; one strong sharp fold on the outer lip, and one long thin fold 

 on the top projecting outwards in a curve. Besides these there is a 

 faint ridge along the top of the whorl close to the outer lip. 



Sutural angle between 90° and 95°. Basal angle about 100°. 

 Greatest diameter observed 1 inch. 



Found in the hippurite limestone at Lisbon and in the subcreta- 

 ceous limestone at the Praia de Ma9ams north of Cintra. 



Plate XIII. fig. 3 a. Exterior. 



Fig. 3 b. Section. 



Nerin^a Conimbrica, n. s. 



Shell turreted, slightly tapering when young, nearly cylindrical 

 when old, almost smooth. Whorls very numerous, increasing slowly 

 in size ; very slightly convex, faintly marked with oblique lines of 

 growth. Suture marked by two delicately impressed hues. Mouth 

 subrhomboidal, with one strong fold on the outer lip and two long 

 curved folds on the columella. Columella solid, small. Four folds 

 in the interior, which reduce the hollow to a narrow complicated 

 passage ; of these, two folds are on the columella, the lower one 

 longer than the other, and both thickest near the extremity ; one 

 large fold on the outer lip, and one long thin fold on the top curving 

 outwards. 



