34 NEW FOSSIL SHELLS 



Remarks. On the upper part of the spire the angle of the whorls is near their middle. 

 Below, it is close to the superior suture. The ribs rise, near the upper part of the 

 whorls, to a short spine, and descend rapidly to the suture, where they become obsolete. 

 The mouth is small and nearly round. 



This little shell I at first thought to be merely the young of S. pachypleura, Conrad; 

 but, as it is but one fifth the size of that species, with the same number of whorls, they 

 cannot be identical. 



S. MICROPLECRA, PL. 36. FIG. 67. 



S. testa elevato-pyramidali, tenui, imperforatd, costulatd; spird attenuatd, conicd, obtusd; suturis parvis, linearibus; an- 

 fractibus sex, convexis; coslis minutis, crebrissimis; anfractu ultimo rotundato; basi lam; aperturd ovatd, marginibus ju- 

 perne disjunctis; labro acuto. 



Shell elevately pyramidal, thin, imperforate, costulate; spire attenuate, conical, obtuse; sutures small, linear; 

 whorls six, convex; ribs very small and numerous; last whorl rounded; mouth ovate, with the margins disunited 

 above; outer lip acute. 



Length .10. Breadth .05 of an inch. 



Remarks. I have felt some hesitation in placing this shell among the Scalariae, as the 

 small costa3 and incontinous peritreme of the mouth seem scarcely to warrant it. 



S. MICROSTOMA, PL. 36. FIG. 68. 



S. testa subulato-conicd, tenui, imperforatd, costata; spird conicd, ve3.de attenuatd, obtusd; suturis imprcssis, intcrruptis; 

 anfractibus septem, valde convexis; costis raris, elevatis, reflexis; anfractu ultimo rotundato; basi sub-carinatd ; aperturu 

 parvd, obliqud, sub-rotunda; labro valde incrassato. 



Shell subulate-conical, thin, imperforate, costate; spire conical, very attenuate, obtuse; sutures impressed, inter- 

 rupted; whorls seven, very convex; costte few, elevated, reflexed; last whorl rounded; base sub-carinate ; mouth 

 small, oblique, sub-rotund; outer lip very much thickened. 



Length .28. Breadth .12 of an inch. 



Remarks. The carina of the base is very small; it does not cross the costae, which 

 continue to the columella. The mouth is unusually small and nearly round. The 

 costa3 are ten in number on the last whorl, quite prominent, and reflexed. In full grown 

 specimens the one which forms the outer lip is much thicker than the rest. The ribs of 

 one whorl do not join those of the next, but lap over very closely. This causes the 

 sutures to be continually interrupted. 



This shell bears a close resemblance to S. acicula, herein described, but differs in be- 

 ing more subulate, having fewer and reflected ribs, and a smaller basal carina. 



GENUS DELPHINULA. 



D. COSTULATA, PL. 36. FlG. 69. 



D. tettd orbiculari, depressd, crassd, costata, striata; spird brevissimd. acuminatd, acutd; suturis linearibus; anfractibus 

 sex, valde convexis, supra planulaiis et leevibus; costis parvis, crebris, transversis, politis; striis longitudinalibus, obliquis, 

 minutissimii; anfractu ultimo rotundato; baii costata; umbilico magno, profundo, intus hevi; aperturd rotunda, supra sitb- 

 canaliculatd. 



Shell orbicular, depressed, thick, costate, striate; spire very short, acuminate, acute; sutures linear; whorls six, 

 very convex, smooth and flattened above; costse transverse, small, numerous, polished; striiE longitudinal, oblique, 

 very minute; last whorl rounded; base costate, umbilicus large, deep, smooth within, mouth round, sub-canaliculate 

 above. 



