60 ORDOVICIAN AND SILURIAN BELLEROPHONTACEA. 



Horizon. — Upper Ludlow. 



Localities. — Ludlow [28079]; Trewerne Hills; Castel Dinas Bran, Llangollen; 

 Brig-steer, Kendal; Frith Farm, Malvern [28078]. 



Remarks. — Good specimens from Ludlow showing the ornamentation and slit- 

 band, such as were described and figured by Moberg and Gronwall (op. cit.), occur in 

 the Jermvn Street Museum [28078, 2807')], and others in the Sedgwick Museum 

 show the slit-band, but not the revolving lines on the surface. The latter are not 

 seen in internal casts, and the type [6700] does not show them, being merely a 

 poor impression of the apertural part of the shell. 



Sowerby's description of the species was very brief : " Spire small, rounded ; 

 aperture very large, two-lobed, twice as long as broad ; sinus broad and short. 

 Length of aperture 7^ lines; width of ditto 11 lines." Though he does not 

 mention the slit-band, yet there is clear evidence of its presence in his figured 

 specimen. 



McCoy's definition of the species is valueless, for he combined shells of more 

 than one type and from more than one stratigraphical horizon. 



It has been believed that Sowerby's II. ;//<</w/»n 1 from the Tilestones of Felindre 

 and Upper Ludlow Bone-bed is identical, 2 but the type-specimen cannot be found 

 and the question must therefore be left unsettled. 



2. Bucaniopsis forbesi, sp. no v. Plate X, figs. 5, 6. 



Specific Characters. -Shell high, of few whorls, nearly involute ; umbilicus very 

 small, about one-fifth diameter of shell, deep, with centre situated at about one- 

 fourth (?) the height of shell. Outer whorl large, rapidly expanding in height to 

 mouth ami less rapidly in width ; dorsum rounded, becoming slightly carinate 

 towards mouth. Mouth large, higher than wide, from half to two-thirds the height 

 of shell. Slit-band rather broad, slightly depressed, inconspicuous (? bearing 

 several closely placed revolving lines), with edges defined and raised. Surface of 

 shell covered with tine cancellation produced by numerous tine sub-equidistant 

 revolving lines parallel to slit-band closely decussated by equally strong gently 

 arched transverse lines meeting slit-band at about (>0°. 



Dimensions. — Height of shell (distorted), c. 20 mm.; height of mouth (distorted). 

 c. 1 2 mm. 



Horizon. — Whitehouse Group, Middle Ordovician. 



Locality. — Shalloch Mill, near Girvan. 



Remarks. — Only two somewhat distorted examples of this shell in Mis. Gray's 

 collection have come under my notice, but they have the ornamentation well 

 preserved in places, and in general characters they resemble Bucaniopsis carinifera, 



1 Sowerby in Murchison's ' Silur. Syst.,' p. 604, pi. iii, fig. 15 ; ibid., p. 613, pi. iv, fig. 50 



2 McCoy, ' Syu. Pal. Foss. Woodw. Mus.,' fasc. ii, p. 309 ; Salter, ' Cat, Camb. Silur. Foss. WocmIw . 

 Mus.,' pp. 68, 192. 



