BRACHIOPODA. 267 



Genus STREPTORHYNCHUS, King. J850. 



PLATE XI, FIGS. 6-17; PLATE XlB, FIGS. 9-15; and PLATK XX. 



1S16. Terebralulite,% Schlothkim. Denkschr. d. K. Akaii. d. Wissenschaft, in Miincheii, vol. vi, p. 28, 



pi. viii, figs. 21-24. 

 1837. Orthis, von Buch. Ueber Delthyris oder Spiiifer uiid Orlhis, p. 62. 

 1848. Orthis, Gkinitz. Vei-stein. d. Deutsch. Zechsteingebirges, p. 13, pi. v, figs. 11-15. 

 1850. Streptorhynclms, King. Monogr. Perm. Fossils England, p. 109, pi. x, figs. 18-28. 

 1853. Orthisma, David.son. Introd. British Foss. Brachiopoda, p. 104, pi. viii, fig. 156. 

 1857. Streptorhynchvs, David.son. British Permian Brachiopod;i, p. 32, pi. ii, figs. 32-42. 



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



1862. StreptorhynchiLS, Davidson. Quart. Journ. Geol. Society, vol. xviii, p. 3, pi. i, figs. 17, 18. 

 1863., Streptorhynchus, de Koninck. Fossiles Paleoz. de I'Inde, p. 37, pi. x. fig. 17. 



1871. (WAis, Quenstedt. Petrefaktenkunde Deutschlands ; Brachiopoden, p. 548, pi. Iv, figs. 51-56. 



.1874. Streptorhynchus, Derby. Carbonif. Brach. Itaituba, p. 35, jds. v, viii. 



1880. Streptm-hynchits, Davidson. British Permian Bi-achiopoda, Suppl., p. 243, pl. xxx, fig. 3. 



1884. StreptorhynchiLS, Waagen. Salt-Range Fossils, vol. i, pp. 576-591, pl. 1, figs. 3-9; pl. Iv, figs. 4-13. 



1887. Streptorhynchus (Orthothetes), OShlekt. Fischer's Manuel de Conchyl., Brach., p. 1284, fig. 10.^)0 



Diagnosis. Shells somewhat trihedral and subpyramidal, 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 

 deltidiuni. Tlie 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 scars 

 strong and flabelliform. 



In the brachial 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 faintly 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, Terebratulites pelargonatus, Schlotheim. Permian. 



Observations. According to Dr. Waagen'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 



