BRACHIOPODA. 267 



Genus S T R E P T K H Y N C H U S, King. 1850. 



I'LATE XI, FIGS. 6-17; PLATE XlB, FIGS. 9-15; anM) PLATE XX. 



1S16. TerebratulUes, Schlotheim. Denkschr. d. K. Akatl. U. Wissonschaft, in Muiicheii, vol. vi, p. 28, 



pi. viii, figs. 21-24. 

 1837. Oi-this, VON BccH. Ueber Delthyris oiler Spirifer und Orthis, p. 62. 

 1848. Ch'this, Geinitz. Veistein. d. Deutsch. Zechsteingebirg-es, p. 13, pi. v, fig.s. 11-15. 

 1850. Streptorhynchus, Kinq. Monogr. Pei-m. Fossils Englaiul, p. 109, pi. x, figs. 18-28. 

 1853. Ori?mina, Davidson. Inti-od. British Foss. Brachioi>oda, p. 104, pi. viii, fig. 156. 

 1857. ISt.reptorhynckvs, David.son. British Permian Bi'achiopoda, p. 32, jil. ii, tigs. 32-42. 



1861. Orthis, Geinitz. Dyas, vol. i, p. 92, pi. xvi, figs. 26-34. 



1862. Streptor?iynchtiS, Davidsox. Quart. Journ. Geol. Society, \ol. xviii, p. 3, pi. i, tigs. 17, 18. 

 1863., Streptorhynchits, de Koxinck. Fossiles Paleoz. de I'lnde. p. 37, pi. x. fig. 17. 



1871. Orthix, QnENSTBDT. Petrefaktenkunde Deutschlands; Brachiopoden, p. 548, pi. iv, tigs. 51-56. 



1874. StrepU>rhyiuhu3, Derby. Carbonif. Bi-ach. Itaituba, p. 35, jils. v, viii. 



1880. Streptoi-kynclma, Davidson. Biitish Permian Brachiopoda, Suppl., \t. 243, pi. xxx, tig. 3. 



1884. StreptwJiynvlms, Waagen. Salt-Range Fossils, vol. i, pp. 576-5P1, pi. 1, figs. 3-9; pi. Iv, tigs. 4-13. 



1887. StreptorhyncJiVS {Orthothetes), CEhlert. Fischer's Manuel de Conchyl., Brach., p. 1284, fig. 1050 



Diagnosis. Shells somewhat trihedral and subpyraniidal, with base convex ; 

 hinge-line shorter than the greatest width of the valves. Pedicle-valve having 

 the beak acute and often incurved and distorted. Cardinal area high, some- 

 what incurved ; delthyrium covered by a broad, imperforate, depressed-convex 

 deltidium. The interior of the valve with low dental ridges terminating in 

 teeth of moderate size ; these ridges are not septiform and do not continue to 

 the bottom of the umbonal cavity ; there is no median septum ; muscular scar.s 

 strong and flabelliform. 



In the bracliial valve the cardinal area is linear, the crural plates are vertical 

 and abruptly elevated on their anterior edges, forming points of attachment 

 for the crura; these unite to form a subcrescentic plate, from the center of 

 which arises a broad, erect cardinal process, which is deeply divided into two 

 lobes, each of which is faintl}' grooved at its summit and on the posterior face; 

 muscular area small, divided medially by a low ridge. Exterior surface 

 covered by fine radiating striae. 



Type, TerebratulUes pelargonatus, Schlotheim. Permian. 



Observations. According to Dr. Wa.a.gen's determination it will probably 

 be necessary to restrict this genus to species agreeing with the above mentioned 

 characters of S. pelargonatus. Though the relationship of this group with the 



