TURBO OR DELPHINULA. 365 
N.B.—The remainder of Pl. XXX is occupied with figures of an interesting 
group of turbinate shells, generally known to me as the Granata-group. This 
group is confined to the Lower Division of the Inferior Oolite, and often to a low 
horizon such as the Opalinus-zone and the lower part of the Murchisonx-zone, but 
is also abundantly represented in the Concavus-bed of Bradford Abbas. 
These depressed and highly ornamented ‘‘ Turbos”’ are characterised by a large 
and infundibuliform umbilicus. Interiorly the aperture is circular, but with a 
subrhomboidal peristome, reminding one greatly of Delphinula, a view which is 
further supported by the character of the umbilicus. Bean seems to have been 
the first naturalist in this country whose attention was drawn to the subject. 
Specimens from the Dogger were sometimes named in his MS. Delphinula 
granata, sometimes Solariwm granatum. Mr. Tawney named a species of this 
group from the Concavus-bed of Bradford Abbas Turbo Shaleri. If, on the present 
occasion, I adopt the double name, it must be understood that ‘ Turbo” is only 
used in a conventional sense, and that to my mind Delphinula is nearer the mark. 
Then comes the question of *‘ species.”’ The relationship of the forms from 12 to 17 
figured in the accompanying plate is obvious, and one might select a much larger 
number of varieties. This is a case where the binomial system of nomenclature 
9> 
is evidently at fault. Whatever specific name is used, in each case the word 
* granata”’ should be understood. 
300. Turso (Detpuinvta) Suateri, Tawney, 1873. Plate XXX, fig. 12. 
1873. Turso Sauer, Tawney. Dundry Gasteropoda, p. 31 (23), pl. ii, fig. 3. 
Description : 
Height 5 . : : By oe) saaan, 
Width : : : : - 125 mm. 
Spiral angle . : > 290952 
N.B.—The largest specimen from Bradford Abbas does not exceed 14 mm. in 
width. Specimens from Dundry, according to Mr. Tawney’s measurements, seem 
to be larger. 
Shell turbinate, widely umbilicate; the spire is regular in some specimens, 
gibbous in others, and ranges from one-third to two-fifths the total height. Apex 
pointed, number of whorls five, sloping easily to a very strong anterior keel, 
which is richly ornamented with rather fine granulations ; in some cases a second 
“keel is exposed in the penult; a fine and almost imperceptible circle of 
granulations also lines the posterior margin. 
47 
