110 PERMIAN FOSSILS. 



Ropsen, in the Zechstein. The next notice we find of it has reference to its Enghsh 

 locahty, and is by Quenstedt, in 1835, who recognised specimens among the fossils 

 collected by M. von Buch at Humbleton Hill. It is also introduced by Mr. Morris in 

 his '^ Catalogue of British Fossils,' as occurring in the latter place. 



Streptorliynclms pelargonatus occurs, though nowhere plentifully, at Humbleton Hill, 

 Dalton-le-Dale, and Tunstall Hill, in the Shell Limestone ; and at Tynemouth Cliff, in 

 the Breccia. Geinitz states that it is found in the lower Zechstein of Ropsen, Corbusen, 

 and Schmerbach; and in the Zechstein-dolomite of Konitz and Altenstein. 



Order Sclerobrachia, Gray, 1848. 



Diagnosis. — "The oral arms" (more or less) "supported by a shelly band arising 

 from the hinder or cardinal edge of the ventral" (dorsal, nobis) " valve."^ (Gray.) 



This Order, distinguished from the last by the character above given, comprises 

 two families, both of which had several representatives during the Permian epoch. 



Family Hypothyrid^,^ Morris, 1846. 



Terebkatul^, Auct. 



Teres, plicate, Von Buch, 1833. 



Tebebkatules plissees {partim), Eudes-Beslongchamps, 1837. 



Cyclothykidjs (jpartim), Phillips, 1841. 



TEBEBRATULiDiE (partim), M'Coy, 1844, King, 1846. 



Rhynchonellid^, Gray, 1848. 



Diagnosis. — "The oral arms are elongate, fleshy, supported at the base by two 

 short, hard, diverging, shelly laminae, arising from the hinge-margin of the ventral valve."® 



The members of this family have a decided approach in form to the ordinary 

 Terehratulida, which has induced many authors to consider both as inseparable from 

 ea^ch other ; but the former differ from the latter in being generally radiately plaited, 

 without a calcareous loop, and having generally "the beak acute, the perforation 

 below it." (Phillips.)* 



Mr. Gray was the first to distinguish the present group of shells, not only as 

 regards separating it from its allies as a family, but to the extent of a sub-class, — 



^ Annals and Magazine of Natural History, 2d series, vol. ii, p. 437. 



2 Mr. Morris only considered the group bearing this name as a sub-genus. (Vide Quarterly Journal of 

 the Geological Society, vol. ii, part, i, pp. 387-8.) 



^ Annals and Magazine of Nat. Hist., 2d series, vol. ii, p. 438. 



* Dr. Carpenter places Hypothyrises in his non-perforated division of the Brachiopods ; but punctures, 

 though much more minute than those in Terebratulidee, occur in every species that has passed under my 

 observation. Punctures also occur in Productidce and Spiri/eridce ; in short, I doubt their absence in any 

 Brachiopod whatever. 



