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. Hebert 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 Maria 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 in 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. Spinigera teinitatis, Tawney, 1873. Plate III, figs. 3 a, b ; 3 c, d, e. 



1873. Alaeia teinitatis, Tawney. Dundry Gasteropoda, p. 12, pi. i, fig. 6. 

 Cf. also Rostellaeia spinosa, Munster. Goldfuss, iii, p. 15, pi. 170, fig. 2. 



Bibliography, 8fc. — 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 Bostellaria spinosa, Munster. 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 1 . . . . .18 mm. 



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 In all cases the canal is excluded. 



