BRITISH SILURIAN BRACHIOPODA. 77 



placed the new English species in Billings' genus. That this new species, however, is not 

 a Centronella will be seen by a comparison of its loop with the loop of C. vir(/o, &c., as 

 described in the preceding ' Devonian Supplement/ 



In the ' Sixteenth Annual Report of the University of the State of New York,' p. 49, 

 Professor James Hall figures and describes a specimen of Terehratula melonica, Barrande, 

 which Dr. Rominger had developed. The lamellae forming the loop are described by 

 Hall as almost parallel and near together, and he states that the loop extends four-fifths 

 of the entire length of the shell, when it is recurved and, turning back, extends two 

 thirds the distance to the beak of the dorsal valve ; and that the crural processes are further 

 from the base of the loop than is represented in the typical figures of Waldheimia, and 

 are opposite the recurved extremity of the loop. 



In pi. cxli, figs. 24, 25, 26, of his magnificent ' Monograph of the Silurian Brachio- 

 poda of Bohemia,' Barrande reproduces Hall's figure of Dr. Rominger's specimen, and 

 describes it as a Retzia (?), but it certainly does not belong to this genus; and I feel 

 disposed to consider both Wald. Mawii and Wold, melonica as the earliest repre- 

 sentatives known of the species of Terebratulse with long loops, and for whose reception 

 the genus Waldheimia was proposed by Professor W. King. 



In external shape Wald. Mawii resembles more or less nearly several other species, 

 especially Rhynchonella (?) rejlexa, de Koninck ; and it is very desirable that the interior 

 of this Carboniferous shell should be examined. 



2. Waldheimia ? Glassii. Dav., Sil. Sup. PI. IV, figs. 4, 4 a, b, c. 



Waldheimia Glassii, Dav. Geol. Mag., New Series, vol. viii, pi. v, fig. 6, 1881. 



Shell small, subpentagonal, broadest posteriorly, slightly truncated in front ; dorsal 

 valve slightly convex, curving rather abruptly at the lateral margins, with a median 

 longitudinal groove or depression commencing about half the length of the shell, and 

 extending to the front ; beak incurved, truncated by a small foramen, hinge-ridges well 

 defined ; surface of both valves smooth, marked by concentric lines of growth. 

 Length 3, breadth 3, depth 2 lines. 



Obs. — About fifteen examples of this species were obtained by Mr. Maw from the 

 washings of some seven tons weight of the Lower- Wenlock Shales of Buildwas. All the 

 specimens procured had about the same dimensions, none exceeding the measurements 

 above given. Only very few of thera were in a perfect state of preservation, and none 

 were in a suitable condition for Mr. Glass's operations, consequently all his endeavours to 

 develop the interior characters proved unsuccessful. It is a rather larger shell than 

 Waldheimia Mawii, but bears some resemblance to it in external shape ; this has 

 prompted me to leave it provisionally with the same genus. 



