294. BRITISH PALAZOZOIC FOSSILS. [GAsTEROPODA. 
surface sharply lineated parallel with the keel, crossed by the strize of growth, which extend obliquely backwards 
to the keel. Length one inch four lines, proportional width ,, length of last whorl ;;. 
I have not seen specimens so elongate as Mr Sowerby’s figure. There are eight or nine of the spiral 
strize in the space of one line. The Plewrotomaria percarinata (Hall) from the “Trenton limestone” does not 
seem clearly distinguished from this species. 
Position and Locality—Common in the green mudstone (Lower Ludlow) of Garden Quarry, Aymestry, 
Herefordshire. 
MURCHISONIA PULCHRA (J/°Coy). Var. PI. 1. K. fig. 42. 
Ref.—Sil. Foss. Irel. t. 1. f. 19. 
Sp. Ch.—Ovate, spire pointed, of six whorls; apical angle 55°; whorls angulated in the middle by the pro- 
jection of the thick keel of the band, which is either obtuse and simple, or divided by two medial fine sulei; 
a second much smaller keel encircles the sutures, which are slightly channelled, and a third small, thread-like 
keel is seen on the body whorl beneath the band ; strize of growth fine, imbricating, irregular in size, directed to 
form the usual re-entering angle of the band. Length four and half lines, proportional width =, length of 
body whorl =. 
The more compact ovate form produced by the whorls of the spire being more numerous, less angulated, 
shorter in proportion to their width, and the additional keel at the sutures, distinguish this species from the 
M. gyrogonia (M°Coy). 
The figure is from an Irish specimen of the typical characters. ‘The less perfect English specimens differ 
in the greater size of the keel above the principal one, but do not seem more than varieties. 
Position and Locality.—In the Bala limestone of Alt yr Anker, Meifod, Montgomeryshire ; in the slates 
N. of Tremadoc, Merionethshire, N. Wales; Bala schists, Mathyrafal, S. of Meifod, Montgomeryshire; sand- 
stone of Mulock Quarry, Dalquorhan, Ayrshire. 
Explanation of Figures.—P\. 1. K. fig, 42, natural size; fig. 42 a, magnified. 
MURCHISONIA SIMPLEX (J7°Coy). PI. 1. K. fig. 44. 
Sp. Ch.—Acutely conical; apical angle 55°; spire of about four or five whorls, angulated in the middle by 
the projection of an obtuse thick keel, another keel a little smaller between the suture and the keel above, and 
a third nearer the suture below on each turn; surface marked with fine strize of growth, arched back to the keel 
at a moderate angle above, and nearly vertical below; base ‘mperforate; width of small specimens six lines, 
length of last turn five lines (imperfect specimens double this size). 
The more elongate form and imperforate base distinguish this species from some of the “Trenton lime- 
stone” varieties of the Plewrotomaria umbilicata (Hall) ; and the same characters, and the absence of the 
spiral strize on the base distinguish it from the Lwomphalus triporcatus (M*Coy). 
I should have supposed the MW. scalaris (Sow. and Salt.), Geol. Journ. Vol. V. t. 1. f. 2, Ayrshire, belonged 
to this, but that one, instead of five keels, are indicated in the figure and text. 
Position and Locality.—Limestone of Alt yr Anker, Meifod, Montgomeryshire ; also in the Caradoc sand- 
stone of Dalquorhan, near Girvan, Ayrshire; greenish trappean sandstone of Glenquaple, Ayrshire. 
Explanation of Figure.—Pl. 1. K., fig. 44, internal cast, natural size. 
MURCHISONIA TORQUATA (M°Coy). PI. 1. L. fig. 19. 
Sp. Ch.—Acutely conic ; apical angle about 26°; whorls six, having a thickened prominent suture, below 
which the upper portion of each is slightly concave, becoming very convex in the lower half; band narrow below 
the middle on the most convex part of the volutions; strie sharp, strongest on the thickened edge of the 
suture, arching obliquely backwards to the band. Length six lines, proportional length of last turn {, 
width =. 
As the collar-like thickening of the upper edge of the suture, nor the greater projection of the lower 
