SPINIGERA. 105 



lations. At the junction with each keel and the varices a spine is developed and 

 generally nearly at right angles to the axis of the shell, sometimes with a slight 

 anterior deflection. These spines are always situated about two-thirds down the 

 whorl ; above the base of each spine is a slight corrugation of the varix but no 

 more than one spine on each side of the whorl. 



Aperture ovate-oblong to subquadrate ; no regular wing, since the anterior 

 lateral spine springs from the varix and not from the outer lip ; canal long and 

 straight. N.B. — There seems a certain amount of irregularity in the development 

 of the spines, but on the whole the arrangement is distinctly bilateral, though in 

 some cases the spines appear better developed on one side than on the other. 



Relations and Distribution. — Nearly related to the succeeding species, Sp. 

 longispina is in this country eminently characteristic of the Humphriesianus-zone, 

 where alone I have succeeded in finding it. The three figured specimens are all 

 from the Sherborne district. The Sauzei-bed at Oborne contains a very inflated 

 variety. Mr. Wilson has lately found a specimen in the iron-shot Oolite of Dundry, 

 which seems to present features intermediate between this species and those of 

 the one next described, though inclining towards Sp. longispina. 



24. Spinigera eecurva, sp. nov. Plate III, figs. 5 a, 5 b ; 5 c, d, e ; 5 /, g, h. 



Description : 



Length (full size) . .22 mm 



Ratio of minor to major axis of width . . 75 : 100 



Shell rather short, fusiform, and moderately compressed. Apical whorls four, 

 subglobular and plain (fig. 5 h), constituting the opening of a very convex spiral 

 angle; next whorl angular and costated longitudinally; the succeeding whorls 

 of the spire (three or four) have either no longitudinals or at best very faint ones, 

 but are spirally ornamented throughout, and betray a tendency to bicarination 

 which varies in different specimens but is generally well marked. The body- whorl 

 exhibits a third carina, sometimes also visible in the penultimate. The chain of 

 bilateral varices is more or less continuous, but a spine is always sent out on both 

 sides where the varix crosses the lower keel (fig. 5 e). The direction of the spines 

 is irregular, those on the body- whorl have mostly a tendency to curve upwards. 



Aperture very nearly quadrate and graduating into a wide and straight canal. 

 There is no actual wing, but in the well-preserved specimen, fig. 5 a, the spines are 

 seen to be grooved, and the groove in the anterior lateral spine is seen distinctly 

 to communicate through a notch in the outer lip with the aperture, hence it may 

 also be said to have the function of a wing. 



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