LAMELLIBRANCHIATA. | UPPER PAL/AZOZOIC MOLLUSCA. 507 
It is proportionally shorter, and less regularly ridged than the S. angustatus (Phill.). Goldfuss’ figure, under 
this latter name, nearly agrees with our shell, and is no doubt identical. 
Position and Locality.—In the impure carboniferous limestone of Lowick, Northumberland. 
Explanation of Figures.—P\. 3.F. fig. 4, right valve, natural size (the diagonal ridge not sharp enough), 
exhibiting portion of the inflected cartilage supports along the hinge-margin. 
SANGUINOLITES suLcatus (lem. Sp.) 
Ref. and Syn, = Hiatella sulcata Flem. Brit. Anim., not Sanguinolaria id. of Phillips. = Allorisma regularis 
King, in M. V. K. Geol. Russ. t. 19. f. 6. 
Desc.—Oblong, dorsal and ventral margins subparallel, slightly arched upwards; very slightly gaping at 
each end; beaks prominent; the anterior end short, contracted by the oblique ovate lunette beneath the 
beaks ; a shallow sinus in the anterior part of the ventral margin opposite the beaks, towards which a wide faint 
hollow (undulating the ridges) extends therefrom ; dorsal lunette, or cartilage support, of moderate width, concave, 
nearly horizontal; sides with subequal, concentric wrinkles (three to four in a quarter of an inch, about the 
middle of the shell), sometimes slightly irregular in passing over the sinal hollow below the beaks, widening 
towards the obscure bounding conyexity of the posterior slope, where they are mixed with numerous coarse strize 
parallel with them ; in young specimens and towards the beaks of all, the wrinkles pass over the posterior slope 
to the hinge-line, but in old specimens towards the posterior end they leave it nearly smooth. Length, two 
40 
inches ten lines, proportional width from beak to ventral margin 4, width of posterior end *8, length of 
anterior end 74, depth of both valves =, width of each cartilage plate one and half lines. Substance of the shell 
very thin; surface marked with longitudinal, membranous, irregular strive, and obscure radiating lines of minute 
rough puncta under the lens, when finely preserved. 
This species is distinguished from the Hdmondia sulcata (Phill. sp.) by the ridges not being split up into 
bundles on the sides and anterior part, by their becoming partially obsolete on the posterior slope, and by the 
shallow depression from the sinus in the margin towards the beak, of which no trace exists in the Z. sulcata, 
as well as in the generic peculiarities of the hinge. Young specimens of this species with the ridges crossing 
the posterior slope have been sent by Prof. King to the Cambridge collection, marked AJ. sulcata, agreeing 
perfectly with his A. regularis as above; so that although it is not clearly so stated at p. 196 of his “ Permian 
Fossils,” it is certain that with his views of the S. sul/cata (Flem. sp.) his Alorisma regularis becomes a synonym 
thereof. 
Position and Locality —Common in the impure carboniferous limestone of Lowick, Northumberland. 
SANGUINOLITES TRICOSTATUS (Porth. Sp.) 
Ref. and Syn.= Cypricardia? tricostata Portk. Geol. Rep. t. 34. f. 17 ?= Pholadomya Visetensis de Ryck. Mél. 
Palit. 10st) land’? 
Desc.—"longate oblong, slightly dilated posteriorly from the elevation of the hinge-line, which is a little 
less than the length of the shell; posterior end obtusely rounded; anterior end very small, oblique, the anterior 
lunette being extremely large, and extending nearly to the ventral margin; ventral margin nearly straight, with- 
out sinus ; beaks moderately large, obtuse ; valves tumid, most so about the middle of the very obtusely rounded 
diagonal ridge, which extends from the beak to the respiratory angle; posterior slope moderately flattened, 
divided by three small equidistant ridges radiating from the beak; surface marked with very numerous, close, 
irregular, small, concentric plicee, and coarse striae, on the sides, parallel with the ventral margin, the coarse 
striz alone crossing the posterior ‘slope, slightly scolloped between the radiating ridges, which they render 
spinulose by crossing; when the periostraca is preserved, rows of minute dots are seen radiating from the 
beak across the concentric plice (about four rows in the space of one line). Length, one inch eight lines, 
proportional width from beak =, length of anterior end #4, width of posterior end ~, depth of one valve %. 
The number of the ridge-like radiating folds on the posterior slope, and the number and small size of the 
concentric plicie, distinguish this rare species from all others. 
Position and Locality—V ery rare in the impure carboniferous limestone of Lowick, Northumberland. 
