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GASTEROPODA OF THE INFERIOR OOLITE. 



The ornaments are somewhat similar to those of 8. pisoliticum, but the 

 proportions differ considerably, as this is a truly conical shell. It occurs in the 

 Freestones of Leckhampton, and seems to be very rare. 



258. Solarium subvaricosum, sp. nov. Plate XXVI, figs. 11, 12. 



Description : 



Diameter (large size) . . . .13 mm. 



Height . . . . .10 mm. 



Spiral angle ..... 90°. 

 Shell conical, moderately depressed, deeply but not widely umbilicated. The 

 form is that of a true cone with a somewhat flattened apex ; nucleus oblique. 

 Number of whorls six, increasing under a regular angle, and rather concave ; 

 sutures distinct. The upper margin of each whorl has a circlet of fine, closely- 

 set granulations, whilst the corresponding ornament at the base of each whorl 

 consists of a circlet of stout tuberculations set widely apart. The interspaces are 

 markedly rugose ; axial lines inclined from left to right, and decussated by very 

 fine spirals. 



The body-whorl occupies somewhat more than half the height of the shell, 

 and is markedly concave, with a blunt carinated margin studded with broad 

 tubercles ; the base is nearly flat, being only slightly raised towards the edge of 

 the umbilicus, where the ends of the curved axial wrinkles are gathered into a 

 ring of tubercles. The base is decussated throughout by a system of fine spiral 

 and growth lines. Aperture subcpuadrate or trapezoidal. 



It <1 at ions and Distribution. — This very typical species of Solarium is obviously 

 related to 8. varicosum, Morris and Lycett. It differs from the Great Oolite 

 species inasmuch as the whorls are concave rather than angular. The umbilicus 

 also in the Inferior Oolite shell is larger and more tuberculated at the margin, 

 and the base less flat. It is also closely related to Solarium formosum, Terq. and 

 Jourd., and to 8. serpmti iunn , Terq. and Jourd., both from the Bathonian of 

 Les Clapes. The Inferior Oolite species is less depressed. 



The smaller specimen (fig. 11) is from the Parkinson i-zone of Aston cutting; 

 the larger specimen (fig. 12) probably from the Inferior Oolite of the Yeovil 

 district, but the exact locality is doubtful. Six specimens are known to me. 

 Those from the Parkinsoni-zone of Aston cutting differ somewhat from the 

 shells of the Dorset- Somerset district. 



