SPINIGERA. 103 
This genus is limited both vertically and horizontally. In England it is almost 
exclusively confined to the Inferior Oolite of Dorsetshire, with a stray specimen 
from Dundry. In France the type species, Spinigera longispina, Desl., is not 
uncommon in the beds of Bayeux. In the singular repetition of the Bayeux-beds 
on a Callovian horizon, which occurs at Montreuil-Bellay, two species of Spinigera 
are found, according to the determinations of MM. Hébert and Deslongchamps. 
The Bathonian beds in France have not yielded any, and this is also the case as 
regards our own Great Oolite. 
The Dorsetshire beds of Inferior-Oolite age, and especially those of Bradford 
Abbas, provide us with some interesting forms. Five species may be noted, of 
which three are probably new. Like Alaria some are monodactyl, as Sp. recurva, 
where the last lateral spine appears to have the function of a wing-digitation ; 
others, like’ Sp. didactyla, have two wing-digitations when adult. The spines are 
in many cases seen to be hollow im section, showing that they were chan- 
nelled or perforated. 
Owing to the compression, which appears characteristic of the genus, it would be 
useless to attempt any comparison by means of the spiral angle. In all cases the 
shell is more or less elongate, fusiform, and compressed. 
22. SpinicERa TRINITATIS, Tawney, 1873. Plate III, figs. 3 a,b; 3c, d, e. 
1873. Aarts rrintraris, Zawney. Dundry Gasteropoda, p. 12, pl. i, fig. 6. 
Cf. also Rostentarta sprnosa, Minster. Goldfuss, iii, p. 15, pl. 170, fig. 2. 
Bibliography, §c.—Mr. Tawney, in describing his species, admitted that the 
materials were very imperfect ; and this we can easily believe, since it would be 
difficult to conjecture from the figure given in the ‘ Dundry Gasteropoda,’ that the 
Specimen was a Spinigera. However, there was enough to distinguish it from 
* Alaria” longispina, Desl. 
Sp. trinitatis is probably closely related to Rostellaria spinosa, Mister. At 
any rate the species from the Jura-kalk of Pappenheim is evidently a Spinigera, 
and resembles this species rather than Sp. longispina, Desl. 
Description : 
Length’. : : : =) Straus 
Ratio of minor to major axis of width .. . 53: 100. 
Shell elongate, fusiform. Whorls of spire extremely flattened, body-whorl less 
so; apical whorls smooth and tumid; next whorl has a median costated keel 
1 Tn all cases the canal is excluded. 
