LAMELLIBRANCHIATA. | LOWER PALAZOZOIC MOLLUSCA. 271 
ANODONTOPSIS ANGUSTIFRONS (M°Coy). Pl. 1. K. fig. 14 and 15. 
Ref—Ild. M*Coy, Ann. Nat. Hist. 2nd Series, Vol. VIT. p. 54. 
Sp. Ch.—Longitudinally subtrigonal, compressed (depth of both valves half the width), diagonally sub- 
carinate from the beaks to the respiratory angle; beaks small but prominent, rather more than one-fourth of 
the length from the anterior end, which is much narrowed and abruptly compressed beneath the beaks, 
produced, rounded, not separated from the body of the shell by any sinus; ventral margin nearly straight ; 
hinge-line short, slightly elevated, forming a wide, compressed, posterior slope, the margin of which is almost 
uniformly arched from the beaks to the respiratory angle, which is obtusely pointed ; surface nearly smooth, a 
few obscure concentric wrinkles of growth near the margin. Width from beak to ventral margin six lines, 
length one inch two lines, width from middle of dorsal to opposite ventral margin =, length of anterior end =. 
Pallial and muscular impression as in the generic characters. 
The more arched and elevated hinge-line and narrow anterior side separate this from the Pullastra levis 
(Sow.), which seems to belong to the same genus ; and the contracted anterior end and greater length separate 
it from the A. quadratus (M°Coy). The posterior lateral tooth or plate extends almost to the end of the 
hinge-line and close to it. 
Position and Locality—Common at Benson Knot, Kendal, Westmoreland, and Kirkby Moor, Kendal, 
Westmoreland. 
Explanation of Figures.—P1|. 1. K. fig. 14. Left valve, natural size; fig. 15, Ditto, right valve. 
ANODONTOPSIS BULLA (A/*Coy). Pl. 1.K. fig. 11, 12, 13. 
Syn.= Lucina bulla (M°Coy), Syn. Sil. Foss. Ireland. PI. 2, fig. 1. 
Sp. Ch.—Orbicular, length slightly exceeding the width, evenly gibbous ; beaks very small, acute, oblique, 
not prominent, one-third the length from the anterior end, which is slightly contracted beneath them ; surface 
with a few membranaceous concentric marks of growth; one small cardinal tooth beneath the beak, and a 
lateral tooth or plate each side of it nearly parallel with the cardinal margin; the posterior largest, double in the 
right valve. Width five lines, length five and half lines. 
The muscular impressions are two, rounded, connected by an entire pallial scar. 
The description is from Irish specimens from the green and purple micaceous sandstone of Galway, the 
British examples before me being less perfect. 
Position and Locality.—Rare in the fine micaceous grits of the Upper Ludlow rock at Kirkby Moor, 
Kendal, Westmoreland. 
Explanation of Figuwres—P\. 1. K. fig. 11. Left valve, natural size; fig. 12, right valve, both from 
Kendal; fig. 13, internal cast from Galway. 
ANODONTOPSIS LA&VIS (Sow. Sp.) 
Syn. and Ref. = Pullastra levis Sow. Sil. Syst. t. 3. f. 1a. 
Sp. Ch.—Subrhomboidal, length about one-eighth less than double the width; beaks small at about one- 
third the length from the anterior end; anterior end broad, rounded; dorsal and ventral margins subparallel, 
slightly convex ; posterior end as wide as the shell, obliquely subtruncate, sides slightly and evenly convex, 
posterior slope slightly convex, defined by an obtuse diagonal ridge from the beaks to the posterior inferior 
angle ; surface smooth or with minute lines of growth; casts shew the short cardinal tooth beneath the beak, 
in the right valve the short, slender, anterior, lateral tooth, the posterior lateral tooth or plate extending nearly 
to the end of the hinge-line and close under it ; anterior adductor impression distinct, ovate, with a small clavi- 
cular ridge extending from in front of the beak to its upper posterior margin. Length one inch one and half 
line, width from beak to opposite margin seven lines, depth of one valve about two lines. 
