NATURAL SCIENCES OF PHILADELPHIA. 21 



PHANEROTINUS, J. Sowerby. 



Phanerotinus paradoxus, n. sp. Shell of medium size, discoid ; whorls 

 four, widely disjoined, rather rapidly enlarging, nearly terete ; spire de- 

 pressed below the level of the outer whorl, causing a slightly deeper concavity 

 above than below the shell ; upper side of last whorl with a scarcely percepti- 

 ble undulation in the middle, and another on the slope of the umbilical de- 

 pression ; under side regularly curved ; faint incremental lines running di- 

 rectly around the whorl. 



Diameter of shell l'O (100) ; diameter of aperture at right angles with peri- 

 pheral line *33 (33) ; same dimension one revolution back from the aperture 

 14 (14). 



The faint appearance of angulations on the upper side may be deceptive : 

 in which case, the greater depression of the spire on that side would indicate 

 it as the base of the shell, and the whorls would be sinistral. 



The only specimen of this unique species so far as I know, the first of the 

 genus noticed in America is in the form of a gutta-percha cast, taken from 

 natural moulis in friable sandstone, of the spiral and basal sides of the same 

 individual. The moulds themselves it was impossible to preserve. The near- 

 est American analogue of this species is Euomphalus laxus, Hall, (Fifteenth 

 Rep. Reg. N. Y., p. 54, pi. vi., fig. 2). 



HOLOPEA, Hall. 



Holopea conica, n. sp. Shell very small; spire elevated, consisting of about 

 three or four rounded whorls, of which the last forms about four-fifths of the 

 entire length ; suture distinct ; aperture lying nearly in the plane of the axis 

 of the spire, ovate, acutely angulated behind, neatly rounded in front ; outer 

 lip thin, regularly convex ; inner lip almost equally convex, slightly thickened 

 by the nearly continuous peristome. Surface not satisfactorily known, but 

 apparently smooth. 



Length -27 (100) ; length of body whorl -20 (74) ; width of body whorl 

 18 (67) ; length of aperture *12 (44); width of aperture "08 (29); spiral angle 

 44. 



This little species generally resembles Holopella mira, but the apical angle 

 is greater, the body whorl more developed and the aperture more angulated 

 behind, with a less continuous peristome. 



Holopea subconica, n. sp. Shell small, breadth equal to its height; spire 

 turbinate, consisting of two or three rounded, rapidly enlarging volutions, 

 bounded by a distinct suture ; aperture subcircular, with a slightly inter- 

 rupted peristome ; outer lip thin ; base gracefully rounded into the minutely- 

 perforated umbilicus, which is closely bordered by the free columellar lip. 

 Surface apparently smooth. 



Height about -15 (100) ; width of last whorl -16 (94) ; height of last whorl 

 09 (56) ; apical angle about 80. 



Associated with Holopea conica and Holopella mira in the calcareous bed 

 "No. 3." 



MACROCKILUS, Phillips. 



Macrochilds pinguis, n. sp. Shell globoid ; spire short, rapidly tapering : 

 volutions not more than five, largely overlapping ; suture moderately im- 

 pressed ; body whorl ventricose, broadest in the middle, somewhat flattened 

 above ; aperture ovate, its longer axis forming an angle of 27 with the axis 

 of the shelJ, acute posteriorly, abruptly rounded anteriorly; inner lip flattened, 

 with indications of a columellar fold. Surface marked by faint directly trans- 

 verse striae of growth. 



Height of shell 1-93 (100) ; height of body whorl 1-41 (73) ; height of spire 

 52 (27) ; length of aperture 1-44 (74) ; width of aperture '93 (43) ; spiral 

 angle 85. 



This species is related to some of the globose forms from the Coal Measures. 



1863.] 



