GAasTEROPODA. | UPPER PALAZOZOIC MOLLUSCA. 537 
STRAPAROLLUS ACUTUS (Sow. Sp.) 
Ref. and Syn. = Cirrus acutus Sow Min. Con. t. 141. f.1; Phill. Geol. York. Vol. II. t. 13. f. 12; 
2 Cirrus tabulatus (Phill.) Sow. Min. Con. t. 638. f. 2. 
Desc.—Conical, spire of seven to eight whorls; apex obtuse; apical angle = to <3; whorls of the spire 
divided nearly in the middle by an angulation or keel, which is rectangular, the portion of shell above it 
flat or concave on the body-whorl, but becoming obtuse on the penultimate, the surface below it convex, 
the angulation gradually disappearing on the whorls near the apex, which are simply rounded ; surface below 
the keel nearly flat, except on the periphery of the body-whorl, which with the under side is very convex, and 
without angulation; umbilicus deep, conical, with a rounded margin. Surface marked with direct, slightly 
irregular lines of growth. Diameter one inch seven lines, proportional width of last whorl ;;;, width of penulti- 
mate whorl +4, total height * to =, height of last whorl * to 3, diameter of umbilicus = to =. 
This species seems closely allied to the S. tabulatus, almost the only difference being the rather more 
numerous whorls, smaller size, and above all the much higher spire, owing to the comparatively small apical 
angle. The above quoted figure of S. tabulatus, from the Mineral Conchology, seems undoubtedly to belong to 
the present species, the two lower fragments on the same plate belonging to my S. crotalostomus. Some 
specimens shew a few obscure, spiral, obtuse strize on the periphery. The depressed specimens in which the 
angulation even of the body-whorl is sometimes obscure, seem to merge imperceptibly into the approximate 
varieties of the S. Dionysii, and from the great width of the umbilicus apparently include my Huomphalus 
anguis (Synop. Carb. Foss. t. 3. f. 11), which merges imperceptibly into such wide varieties of S. Dionysit as 
de Koninck figures (Anim, Foss. Bel. t. 24, f. 1 and 2); all these variations are exhibited by the specimens in 
the Cambridge collection. 
Position and Locality—Not uncommon in the carboniferous limestone of Derbyshire ; in the black lower 
carboniferous limestone of Isle of Man; in lower carboniferous limestone of Kendal, Westmoreland. 
STRAPAROLLUS? CALYX (Phill. Sp.) 
Ref. and Syn. = Euomphalus calyx Phill. Geol. York. Vol. IL. t. 13. f. 3; Min. Con. t. 633. f. 8, 9, 10. 
Desc.—Discoid, semiconical, depressed, of five or six gradually increasing whorls, those of the spire sunk 
rather below the level of the outer whorl; periphery very broad, sloping outwards and forwards with slight con- 
vexity, bounded by nearly equal, narrow, obtuse, prominent keels, that of the under side bounding the umbilicus, 
and marking the greatest diameter of the shell; on the upper side the shell slopes at about 80°, with slight con- 
cavity from the keel to the simple sutures, the keel being a little outside the middle on the turns of the spire ; 
umbilicus very wide, steep, conical, sloping with little convexity from the keel to the centre, the sutures coin- 
ciding with the keel on the spiral turns. Surface crossed by nearly direct, irregular, obscure lines of growth ; 
mouth subtriangular, the lower side longer than the upper. Greatest diameter and width of umbilicus one inch 
six lines, proportional diameter across the upper keels , proportional width of last whorl ==, width of penulti- 
mate whorl +4, depth of last whorl =; . 
The great width of the steep conoidal umbilicus, and its bounding keel forming the greatest diameter of 
the shell, and the consequent regular outward slope of the periphery, and greater proportional depth of the last 
whorl, separate this species easily from the 8. catillus. I haye never clearly seen the inner lip of this species, 
but it is figured by Sowerby as continuous. 
Position and Locality—Rare in the carboniferous limestone of Derbyshire. 
STRAPAROLLUS CARBONARIUS (Sov. Sp.) 
Ref. and Syn. = Euomphalus carbonarius Sow. Min. Con. t. 633. f. 4 to 7.= Euomphalus quadratus M°Coy, 
Synop. Carb. Foss. Irel, t. 5. f. 22. 
Desc.—Discoid, depressed, of four or five rapidly enlarging whorls ; spire depressed below the level of the 
body-whorl ; whorls quadrate, flattened above and below; periphery bounded by two equally strong, prominent 
3 z 2 
