96 FAUNA OF THE CORNBRASH. 



the columella. Length 14"', diameter 10"', length of aperture 11'"." From 

 Scarborough. In the Sedgwick Museum. 



Description. — Hudleston redescribes the specimen and says spiral angle 78°, 

 the 6 upper out of 7 whorls are beautifully preserved, the apical four being trans- 

 parent, or free from interior matrix. The furrows which border the suture are 

 bounded externally by a deeper line, beyond which the rounded bend of the whorl 

 rises. On the body whorl the lines of growth are well marked, and with the 

 light shining along the spirals indications of numerous light and dark colour bands 

 may be seen. The inner line of the aperture crosses the axial line at an angle of 

 about 40°. 



Distribution. — This species appears to be entirely a Yorkshire form. Including 

 the two following species or varieties, 17 specimens have been seen in all. A cast 

 of the present species is included in the Porter collection (hence it is included 

 in H. B. Woodward's list). There is no proof, however, that it came from 

 Peterborough, and the matrix is more like that of Yorkshire. 



Relations. — The Acteoninse being Yorkshire shells which appear to die out 

 completely with the Cornbrash, their allies must be sought for in the underlying 

 beds; but they are essentially, as witnessed by the remarkable preservation of their 

 thin shells, autochthonous fossils. They have probably grown and varied together 

 through the Avhole course of their existence, and it matters little therefore whether 

 we call the three forms which may be recognised varieties of one species or 

 separate species. In the latter case the name is preserved for the present form, 

 which is the central type. They may become thinner in proportion and longer 

 at the base {elongata) or stouter in proportion and squatter at the base (cinerea) ; 

 one of these varieties having received a specific name, there is no reason why the 

 other should not. 



Acteonina elongata, sp. no v. Plate IX, fig. 2. 



1885. Acteonina scarburgensis, Hudleston, Geol. Mag. [3], vol. ii, p. 204, "elongate variety," pi. v, 

 fig. 9. 



Type. — Length (apex gone) 34 mm., greatest breadth 16'5 mm., or ratio of 

 breadth to length 10 : 20-|. Any furrows along the sutures are very obscure. 

 Shoulder much rounded. Length of aperture 24 mm. Spiral angle 70°. The 

 columella is seen to be curled over as a whole, leaving an apparent umbilical 

 furrow. The rest of the details as in A. scarburgensis. From Scarborough. In 

 the collection of Mr. Hudleston. 



Distribution. — There are four at least which answer this description, and pro- 

 bably some of the others included in the general series. It is probably this species 

 which is enumerated in Hudleston's list as A. gigantea, but not otherwise referred to. 



