208 PERMIAN FOSSILS. 
(2?) Rissoa MINUTISSIMA, Brown. Op. cit., vol. i, p. 64, pl. vi, figs. 12, 14. 
— — AND oBTUSA, Brown. Brown, Fossil Conchology, p. 79, pl. xxxvii*, | 
figs. 28-30, 34-36. 
— — — a0 Morris, Catalogue, p. 161, 1843. 
— — — a De Verneuil, Bull. Soc. Géol. de France, 
2™ serie, vol. i, p. 36, 1844. 
— — — 45 Geol. Russ., vol. i, p. 225, 1845. 
— — = < Tennant, Strat. List, p. 89, 1847. 
(?) Trocuvs PusILLUs, Geinitz. Versteinerungen, p. 7, pl. i, figs. 15, 16, 1848. 
Diagnosis.—“ Shell ovate, smooth, ventricose; spire nearly equal to the body in 
length, consisting of three depressed, subturreted volutions, divided by a deep suture ; 
aperture nearly orbicular; pillar lip not reflected, but provided with a slight umbilicus 
at the base of the columella. Length upwards of a quarter of an inch; diameter not 
quite so much.” (Brown.') 
There is in one of the original specimens of this species belonging to Mr. Binney an 
important character, which Captain Brown seems to have overlooked, namely, a broad 
sinus in the upper half of the outer lip, as indicated by the incremental lines, which 
are represented in fig. 18, Pl. XVI. This character throws considerable doubt on the 
present generic position of the species; and somewhat favours the view that it belongs 
to the genus d/acrocheilus. 
fissoa obtusa is recorded as occurring in the Magnesian Marls at Collyhurst 
(Captain Brown): it also occurs in the same formation at Bedford, ten miles west of 
Manchester (Binney). 
Rissoa Leieui, Brown. Plate XVI, fig. 15. 
Rissoa Letent, Brown. Trans. Manch. Geol. Soc., vol. i, p. 64, pl. vi, figs. 9-11, 1839. 
= — » Fossil Conchology, p. 79, pl. xxxvii, figs. 25-27, 1841. (?) 
— — 6 Morris, Catalogue, p. 161, 1843. 
—- .,- i De Verneuil, Bull. Soc. Géol. de France, 2™* série, vol. 1, p. 36, 
1844, 
— — Ss Geol. Russ., vol. i, p. 225, 1845. 
— — a Tennant, Strat. List, p. 89, 1847. 
Diagnosis.—“ Shell] smooth, oblong-ovate ; spire long, consisting of four deeply 
divided, inflated volutions, terminating in a somewhat obtuse apex; aperture ovate, 
slightly contracted above, and rounded at the base ; columella subumbilicated. Length 
one eighth of an inch; breadth one fourteenth of an inch.” (Brown.?) 
“Found in the Magnesian Mar] at Coilyhurst, and is in Mr. Binney’s cabinet.”* 
1 Transactions of the Manchester Geological Society, vol. i, p. 118. 
2 Ibid., p. 64. 
3 Vide Brown’s Fossil Conchology, p. 79. 
