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SUPPLEMENT TO THE CRAG MOLLUSCA. 



according to information furnished me by the late Dr. Woodward, a memorandum on the 

 back of the tablet, stating that it came from the Nar Brickearth, where the shell has been 

 found by Mr. Rose. I have, therefore, omitted the locality of Bridlington for it. The 

 figure in c Crag Mollusca ' is not quite accurate, the posterior side being a little too 

 rounded for the general form of the Crag specimens. 



Montacuta ferruginosa, Mont. Crag Moll., vol. ii, p. 129, Tab. XII, fig. 14. 



Localities. Cor. Crag, Sutton, and near Orford. Chillesford Bed, Alcleby. 

 Specimens of this species were among the shells from time to time sent me for 

 examination by Messrs. Crowfoot and Dowson from Aldeby. 



Montacuta elliptica, S. Wood. Supplement Tab. X, fig. 21. 

 Locality. Coralline Crag, Sutton. 



The above figure represents a specimen of Montacuta, which appears to be distinct 

 from the shell called bidentata. It has the posterior side more rounded and more extended 

 than bidentata, and is less inequilateral. It is also less compressed and more elliptical, 

 and has the denticles comparatively longer. 



Genus. — Sphenalia (see ante, p. 121). 



Sphenalia donacina, S. Wood. Crag Moll., vol. ii, p. 131, Tab. XI, fig. 3 fas Monta- 

 cuta ? donacina) . 



Localities. As in Crag Moll. 



A Coralline Crag shell from Sutton was described in the ' Crag Mollusca ' under the 

 above provisional name. It, however, does not in the hinge accord with Montacuta 

 bidentata, the type of the genus Montacuta, and I have accordingly changed its position. 

 I am sorry to say that the Crag fossil is still very rare in my collection. A recent British 

 specimen has been procured by Mr. Jeffreys, which he has referred to my species, and he 

 is equally at a loss where to place it. He says ('Brit. Conch./ vol. 'ii, p. 216), "in 

 shape it is a miniature Zenatia, a genus founded by Dr. Gray, but having an external 

 ligament." The shell, however, given by Messrs. H. and A. Adams as the type of 

 Zenatia ('Gen. of Recent Moll.,' vol. ii, p. 384, plate cii, fig. 1, Z. acinaces) is an 

 aberrant form of Lutraria, with a deep sinus in the mantle mark. The nearest approach 

 to this species seems to me to be the succeeding species substriata. 



