SUPPLEMENT. 485 



440. Cerithium (Colixa^) Lycetti, sp. nov. Plate XLIII, figs. 22 a, 22 h. 



Description : 



Height . . . . .15 mm. 



Bocly-wborl to total height . . . 35 : 100. 



Spiral angle . . . . .35°. 



Shell sub-fusiform ; apex sharp ; spire regular ; number of whorls eight, 

 sutures close fitting. The ornaments consist of wide-apart longitudinal varices, 

 which are decussated by strong spiral lines, slightly nodular. 



The body-whorl is considerably expanded so as to make the outer lip patulous. 

 The longitudinal varices are scarcely to be traced in the body-whorl, which is 

 ornamented by numerous spiral ribs, expanding outwards with the increase of the 

 whorl and causing the margin of the lip to be crenulate. The aperture is oblique 

 with a full and rounded outer lip, somewhat flattened anteriorly, with a sinuous 

 and rather encrusted columella, which terminates in a broad, short notch turned 

 outwards almost at right angles to the axis of the shell. 



Relations and Distribution. — This form is very different to the general facies 

 of the shells in the Inferior Oolite which have been referred to Cerithium. It is 

 suggestive of Pyramis and other sub-genera of Potamides, but these are at least 

 brackish- water shells. On the other hand, its resemblance to such shells as 

 Geriihium {Golina) contractum, Sow., and Geritliium {Golina) tsdiiiatum from the 

 Indian Ocean (Natal) is very striking. Provisionally we may refer the Oolite 

 specimens to Golina. Mr. Wilson considers that, possibly, there is a generic 

 aflBnity between G. Lycetti and the Upper Lias Nortonia Patrocliis. 



Erom Nailsworth (Oolite Marl or Pea-grit) there are four specimens in the 

 Jermyn Street Museum (Lycett Collection). The figured specimen is the most 

 elongate. 



441. Bkachytrema, sp. Plate XLIII, fig. 23. 



An imperfect specimen with an estimated height of 15 mm. and a spiral angle 

 of 40°. The aperture, which happens to be well-preserved, is widely sub-quadrate 

 with an eflFuse outer lip ; columella much twisted near the base, with a broad 

 gutter or notch directed outwards at an angle of 45°. There is strong granu- 

 lated spiral ornamentation throughout the shell, which ajDpears to have been 

 very thick. 



This seems to be a typical Brachijtrema. A single specimen from the Irony 

 Nodule-bed, Burton Bradstock. 



1 H. aud A. Adams, 1853. 



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