DELPHINULA. 363 
bordering the umbilical excavation being roughly serrated. The umbilical hollow 
terminates in a true umbilicus of considerable depth. Aperture circular, with an 
expansion of the inner lip, so as to produce a slight projection towards the 
columellar extremity. 
Relations and Distribution.—This form occurs rarely in the ‘‘ Base-bed”’ at 
Lincoln, and also at Stoke Lodge. I possess a specimen, considerably larger than 
the one figured, said to have come from the Inferior Oolite of Rodborough Hill. 
298. DELPHINULA ALTA-ACANTHICA, sp. nov. Pl. XXX, fig. 9; variety, fig. 10. 
Description : 
Height : : : : _ mm: 
Width : ; + LOimm: 
Differs from the preceding chiefly in the more gaping suture, in the freedom 
from bicarination, which is especially marked in the body-whorl ; and, above all, 
in the great size and length of the spinous processes (hollow) on the single carina 
situate at the angle of each whorl. 
Relations and Distribution.—It is just possible that this form may represent 
D. alta, M. and L., under circumstances which permit of its bizarre ornamentation 
being preserved. 
Excellent specimens are occasionally obtained from the ‘ Base-bed” at 
Lincoln. Hitherto I have not noticed this particular form elsewhere in the 
Inferior Oolite. 
DELPHINULA ACANTHICA, var. DEPRESSA, fig. 10. 
Description.—Height 4:3 mm.; width (without spines) 65 mm. Number of 
whorls the same as in the more usual form, but all extremely depressed. The 
penult and body-whorl are flattened out, angular, muricated, and furnished with a 
keel, which produces wide-apart, upturned spines, whose length keeps increasing 
anteriorly until a very salient projection is attained. 
This is the most bizarre of all the forms connected with this group of 
Delphinula. For comparison vide list given supra. It is just possible that 
Euomphalus coronatus, Sow., may be a micromorph, though, if Sowerby’s enlarge- 
ment is to be relied on, that shell is more likely to be a Straparollus. 
Rare in the ‘‘ Base-bed”’ at Lincoln. 
