74 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Costfe rotundatae, retrorsse, fere ad carinam obtusam ductse, et faciem 

 uinbilicalem attingentes; striae accretionis primum rectse reticulata^, 

 deinde vina cum costis retroflexge, crenulatae. 



I should have thought, with Prof. M'Coy, that this was Cyrto- 

 lites ornatus, Conrad ; but in Hall's figure, and in specimens from 

 New York, the lines of growth are direct across. In that species, 

 too, the umbilicus has a sharper edge, and the plaits do not go at all 

 within it. B. nodosus is sometimes as large as the American species. 



Localities. Llandeilo and Bala rocks ;— S. of Llangollen ; Bedd- 

 gelert; Llanfyllin ; Hope Bowdler, Shropshire ; in beds "3" of sec- 

 tion, p. 64. 



2. Bellerophon (Bucania) sulcatinus, Emmons ? 

 (Hall, Pal. New York, Part 1. t. 6. f. 10?) 



B. uncialis et ultra, convolutus, anfractibus a dor so convexiusculo depressis, 

 striatis. Carina lata, plana, (sublsevis ?) marginata, vix elevata. Strise 

 concentricse fortes, circiter 10 (ad carinam ssepissime interstriatse et in 

 a3tate plurimse), a lineis crebris valde reflexis undique decussatae. Aper- 

 tura lata, expansa, sinu profundo. 



This very beautiful shell differs from B. sulcatinus, as figured by 

 Hall, in having regular ribs towards the angular edge, which become 

 interlined and form a broad band of close strise as the shell grows 

 older. The umbilical face, too, is free from ribs, which I have some 

 reason to think is not the case with B. sulcatinus. The strise, too, 

 on that shell, appear to meet at a very much more obtuse angle than in 

 ours. It should be called B, lingualis, if the above characters are 

 sufficient to separate it. It must have been a very thin shell. 



Bellerophon acutus. Sow., appears to be quite a distinct species 

 from the B. carinatiis. Sow. It has a very acute keel, and flat, 

 almost excavated, sides, strongly striated ; the umbihcus is very 

 large, and sharp-edged. Now that good specimens are obtained from 

 Horderley (with the species above described), it is clear that the 

 Ayrshire shell figured under this name in the Quart. Geol. Journ. 

 vol. vii. PI. 9. f. 18. is distinct. It has a small umbilicus with a 

 rounded edge, and the sides are comparatively convex. It may, 

 however, be a variety of B. carinatus. 



In upper part of beds "4" of section, pp. 64, &7. 



3. Strophomena bipartita, n. sp. 



S. semiovalis, radiatim crebristriata, angulis haiul extensis. Strise a3quales 

 costis prominulis (nisi in areis cardinalibus) interruptse, costa medians 

 maxima elevata in duas partes testam dividente. Testa uudique lineis 

 coucentricis omata, margine cai'dinali ssepe coiiiigato. Valva ventraHs 

 lente convexa, intra lameUis brevibus ad augulum 90° divaricatis, area 

 angustissima. Altera plana (costis minus conspicuis) dentibus externis 

 distinctis ad angulum 80° divergentibus : dentes interni (fidcrum eardi- 

 nale) duo, paralleli, angustissimi, externis breviores. Long. imc. 1, lat. 

 unc. \\. 



The striation of this flattened shell is a good deal like that of 

 iS". ffrandis, which, however, has the dorsal, not the ventral valve the 

 more convex; the interior differs much. The remarkable central ridge, 



