110 CARBONIFEROUS LAMELLIBRANCHIATA. 



Localities. — England: the Redesdale Ironstone Beds, Redesdale, Northumber- 

 land. Scotland : Lower Carboniferous of Thornton Burn, Haddington. 



Observations. — This species has the characteristically expanded anterior side of 

 Streblopteria, but with a short hinge-plate. It differs from other described species 

 of the genus in having the left valve ornamented with flattened ribs covered with 

 fine radiating lines, while the right valve is smooth. The interior of the valve also 

 shows the flat ribs. The majority of the species of the genus are smooth, but even 

 in some of these there are well-marked radiating colour-bands. 



De Koninck describes two of his species, L. ellipsoidea and 8. pleurophora, as 

 having radiating strias. In the former these striae arise some distance from the 

 umbo, and in the latter it is stated that the striae are more marked near the 

 margin ; but it is not noted that only the left valve is so ornamented, though it is 

 the left valve which is figured in both cases. 



P. Redesdalense resembles P. propinquum, de Koninck, in general shape, and it 

 is possible that the species may be one; but no radiating ribs are figured or 

 described as being present in the Belgian shell. 



In Prof. Lebour's list of the shells from the Redesdale Ironstone beds (' Hand- 

 book Geol. and Nat. Hist. Northumberland and Durham,' p. 121) four species of 

 Aviculopecten are enumerated, namely, A. planoradiatus, M'Coy; A. papyraceus, 

 Sow.; A. coiicavus, M'Coy; A. coelatits, M'Coy, and a new species. It is probable 

 that P. Redesdalense was mistaken for A. pJanoradiatus, which I have not met with 

 there; but the hinge, ears, and general shape of the shell are very different. Of 

 course, Pterinopecten papyraceus does not occur at this locality. 



Pseudamusium sublobatum, Phillips, sp., 1836. Plate XVII, figs. 11 — 14. 



Avicula sublobata, Phillips, 1836. Geol. Yorks., pt. ii, p. 211, pi. vi, fig. 25. 



Brown, 1849. Must. Foss. Couch., p. 162, pi. lxvi**, fig. 32. 

 Aviculopecten sublobatus, Morris, 1854. Cat. Brit. Foss., 2nd edit., p. 166. 



B. Etheridge, jun., 1876. Geol. Mag., dec. ii, vol. iii, 

 p. 151, pi. vi, figs. 2 — 6. 



Specific Characters. — Shell below medium size, slightly obliquely oval, somewhat 

 inequivalve, (he lel'l valve regularly and very convex, the right less so. The 

 greater pari of the margin of the valve regularly curved, but the curvature 

 apparently terminating both in front and behind in a kind of shoulder, above 

 which the edge of t he valve slopes inward to the base of each ear. The hinge- 

 Line probably \rv\ short. The right anterior ear small, but deeply separated from 



