350 CARBONIFEROUS LAMELL1BRANCHIATA. 



referred to Bolland are to be obtained in the Craven district. A series of five 

 well-preserved but small specimens of this species are in the Museum of the 

 Geological Survey, Jermyn Street, and Mr. E. J. Garwood has collected several 

 examples from the so-called knoll reefs between Cracoe and Burnsall in Craven. 

 Mr. Goodchild refers a number of specimens, in the Armstrong Collection of the 

 Edinburgh Museum of Science and Art, and in the collection of the Geological 

 Survey, to the Venus parallela of Phillips, and states that in his opinion this 

 species should be referred to Gypricardella of Hall. I expect that he has mistaken 

 G. crebricostata of Armstrong and some of the other species of the genus which 

 occur in Scotland for Phillips's shell. He evidently is in error in supposing that 

 the Gypricardia rhombea of authors has any relationship to G. parallela, for it 

 belongs to a totally different genus, and I have not met with any specimens of 

 that shell from the Carboniferous beds of Scotland. Fig. 6, PI. XXXIX, is a 

 curious variety, differing much in contour from the type of the species. As it is 

 the only specimen of its kind, I hesitate to erect a new species for it, and for the 

 present suggest that it may be a mere sport. 



Gypricardella ooncenteica, sp. nov. PI. XXXIX, figs. 8 — 11. 



? Venus elliptica, Young and Armstrong, 1871. Trans. Geol. Soc. Glasgow, 1871, 



vol. iii, Supplement, p. 54. 

 ? — — Young, Armstrong, and Robertson, 1876. Cat. West. Scot. 



Eoss., p. 55. 



Specific Characters. — Shell small, subcircularly quadrate, very moderately 

 gibbose, slightly inequilateral, very obscurely carinate. The anterior end com- 

 prises the anterior third of the valve, and is compressed and narrowed ; its border 

 rounded, forming with the inferior border as far as the postero-inferior augle a 

 single almost semicircular curve. The posterior margin is almost straight and 

 obliquely truncate from above downwards and forwards, forming a well-marked 

 almost right augle with the hinge-line, and being bluntly rounded below into the 

 inferior border. The hinge-line is arched, straight, depressed, and often bent 

 downwards on itself posteriorly. The umbones are small, pointed, incurved, 

 contiguous, tumid, slightly raised and placed in front of the middle line. The 

 lunule is narrow, steep, and elongate, the escutcheon broad, deep, and loug, 

 marked off from the dorsal slope by an erect, narrow, slightly curved, angular ridge, 

 often bent on itself. Passing downwards and obliquely backwards from the 

 umbones to the postero-inferior angle is an obscurely angular ridge, which 

 separates the compressed and hollowed dorsal slope from the rest of the valve, 

 which is regularly but very gently convex. 



