506 BRITISH PALASOZOIC FOSSILS. | La MELLIBRANCHIATA. 
at the diagonal ridge; hinge-line not quite so long as the shell; inflected margin slightly concave, moderately 
wide ; surface under the lens covered with very minute granules, less than their diameter apart. Average length 
one inch two lines, in proportion thereto greatest width from beak to ventral margin 3, width of posterior 
end ;;;, length of anterior end +, length of anterior lunette 7, depth of both valves ,*). 
Professor King mentions the pallial sinus of this species being shallow, and figures it very distinctly. A 
specimen sent to the Woodwardian Museum, supposed to exhibit this character, shews a mark very different in 
form, and in my mind not due to the pallial scar at all, nor have I ever seen a sinuated pallial scar in any shells 
of the kind. As Count Keyserling’s figure and description seem to have long had the priority over Professor 
King’s first description (in his catalogue), I think it but just to adopt his name. 
Position and Locality —Rare in the Permian limestone of Humbleton. 
SANGUINOLITES STRIATO-LAMELLOSUS (de Kon. Sp.) 
Ref. and Syn. = Cypricardia striato-lamellosa de Kon. Anim. Foss. Pel. t. H. f. 8. 
Desc.—Elongate, oblong, compressed, increasing slightly in width towards the posterior end, which is 
obliquely bitruncate ; beaks moderate, pointed, oblique, moderately incurved; anterior side short, compressed, 
semielliptically rounded, with a very deep ovate lunette beneath the beaks ; hinge-line considerably shorter than 
the shell, rendering the anal angle very obtuse; cardinal margins inflected nearly at right angles to form the 
moderately wide, narrow, posterior lunette or cartilage support, which is bounded by a strong ridge; ventral 
margin nearly straight, sometimes with a very minute obsolete sinus in the middle, from which a faint obsolete 
sulcus extends towards the beak; sides very slightly convex; diagonal ridge from beak to respiratory angle 
very sharply defined throughout, angular; posterior slope flattened, divided in the middle by a strong angular 
ridge, the projection of which forms an obtuse angulation in the middle of the posterior margin. Surface 
marked with sharp, regular, concentric lines of growth, and after about three lines from the beak, with flat 
imbricating laminze, averaging one line wide, most strongly marked towards the margin of old specimens. Casts 
shew the impressions of the large anterior and posterior adduetors connected by the distinctly marked, simple, 
pallial scar. Average length of the British specimen, from anterior to posterior end, nine lines, in proportion 
44 50 
thereto width from beak to opposite ventral margin +, width of posterior end *, length of hinge-line from 
beak /°, length of anterior end ,;, greatest depth of both valves (at middle of diagonal ridge) =, (reaches one 
inch four lines long in Belgium). 
The single specimen described by de Koninck was larger than any of ours, and shews the broad concentric 
lamellee more distinctly for this reason. As I have seen all the generic characters there can no longer be any 
doubt of the genus. The small byssal furrow is remarkable for its backward position, but is obsolete on seyeral 
specimens, as in M. de Koninck’s type. 
Position and Locality.—Common in the shales of the carboniferous limestone of Craige near Kilmarnock ; 
rare in the impure carboniferous limestone of Lowick, Northumberland. 
SANGUINOLITES SUBCARINATUS (J/°Coy). PI. 3. F. fig. 4. 
Ref.—M ‘Coy, Ann. Nat. Hist. 2nd Series, Vol. VIT. 
Desc.—Flongate, oblong, tumid; beaks very large, obtuse, near the small, rounded, anterior end, in which 
there is an abruptly hollowed lunette beneath the beaks; posterior end narrow, square, truncated; diagonal 
ridge angular, slightly sigmoid, strongly defined from the beak to the respiratory angle ; posterior slope smooth, 
slightly concave, divided nearly in the middle by a ridge-like fold from near the beak, becoming nearly obsolete 
at the end; sides slightly flattened, with coarse irregular strize and irregularities of growth parallel with the 
margin; ventral margin nearly straight, slightly convex ; hinge-line as long as the shell; its inflected margin 
broad, slightly concave, nearly at right angles to the plane of the margin of the valves; length one inch four 
lines, proportional width from beak 44, width of posterior end ;;, length of anterior end ;;, depth of one valve 
createst about the middle of the diagonal ridge) >. 
This rare species is remarkable for its narrow, square, posterior end, and strong angular diagonal ridge. 
