GASTEROPODA. 29 
DENTALIUM PaRKINSONI, Quenst. Der Jura, p. 484, t. 65, figs. 5, 6. 
_ ENTALOIDES, Oppel. Die Juraformation, 1856-8, p. 390. 
— ANNULATUM, Bean, Leckenby. Journ. Geol. Soc., 1858, vol. iv. 
Testa crassa, tereti, subarcuata, sepius nitida, striis tenuissimis densissimis paululim 
obliquis ornata. (Deslongchamps.) 
Shell thick, tubular, round, smooth, shining, slightly curved ; encircled with striations, 
which are somewhat oblique and strongly impressed towards the posterior or smaller 
extremity, anteriorly they are more faintly and densely arranged and ultimately disappear, 
the surface having some irregular annular folds of growth. Length of an imperfect Corn- 
brash specimen 24 lines, the larger diameter 2: lines. 'The Calcareous Grit examples have 
larger dimensions, they are of more advanced growth, and have the greater portion of their 
cylinder devoid of striations. 
The Cornbrash imperfect specimens are less slender and more straight than the figures 
of D. Parkinsoni given by Professor Quenstedt, and more nearly accord with those of 
__ D. entaloides, Deslongchamps; but the specimens figured by Quenstedt differ also from 
each other in their attenuation and curvature. Dentalium cinctum, Goldfuss, has encircling 
striations, without obliquity; D. wxdulatum of the same author has the figure some- 
what compressed ; D. tenue, Goldf., is more slender and more nearly cylindrical. 
Geological Position and Locality. Dentalium entaloides appears to have a considerable 
geological range; the Cornbrash of Scarborough has produced a few specimens; Mr. 
Leckenby has also obtained it in the Keliloway Rock and the Calcareous grit of the same 
locality. D. entaloides was obtained by M. Deslongchamps in the Inferior Oolite of 
Moutiers and Bayeaux; by Dr. Oppel in the beds with Ammonites Parkinsoni at Mont 
d’Or, near Lyons; in Swabia it occurs at the upper boundary of the Lower Oolite (Braun 
Jura e. Quenst.) at Ehningen and Balingen. 
Trocuus strigosus, Lyc. Tab. XLV, fig. 12. 
Testa alta, conica, transversé costellata, costellis granulosis equalibus ; anfractibus (5) 
subplanis, quadricostatis et vitta striata anteriora ; ultimo anfractu obtusé carinaté ; basi 
concava ; columella obliqua ; apertura sub-triangulari. 
Shell elevated, conical, transversely costellated ; costelle, four to a volution, granulated 
and equal; the anterior border of each volution has also a depressed, striated band ; the 
volutions, about five in number, are flattened, and the last volution is rounded; the base 
has a few striations; the columella is oblique, and the aperture somewhat triangular. 
The ornamentation is strongly marked and regular; the height and breadth are nearly 
equal; the sole specimen is rather imperfect at the apex. 
Geological Position and Locality. The Cornbrash of Gristhorp Bay, near Scar- 
borough, in the collection of Mr. Leckenby. 
