NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA GRANT I4I 



preserved specimens in the U.S. National Museum collections, and a 

 species from the Permian of Timor, known through work by Broili 

 ( 1916) . Species of Stenoscisma will be discussed more fully in a forth- 

 coming paper by Cooper and Grant on Permian brachiopods of West 

 Texas. 



Stenoscisma is the culmination of the development of the Steno- 

 scismatacea. Its species attain greatest development of the features that 

 typify the superfamily, and its evolution seems to have embodied the 

 dominant trends in the history of the superfamily. The stolidium is 

 best developed in species of Stenoscisma, although it is only sporadi- 

 cally present on some species (e.g. 5\ hueconianum (Girty)). Costa- 

 tion varies from fine and nearly complete (S. multicostum Stehli) 

 through broad and covering only about half the shell (S. venustum 

 (Girty)) to erratic, with some individuals nearly smooth (S. schlo- 

 theimi (von Buch)). No species of Stenoscisma develops sharp, fine, 

 numerous costae such as those of the uncinuliform genus Torynechus; 

 such costae are atypical for the superfamily. Internally, the spondylium 

 and camarophorium are large and well-formed in most species of 

 Stenoscisma, the muscle marks visible, and the pallial markings 

 strongly inscribed. 



No descendants of Stenoscisma are known. Apparently the entire 

 superfamily became extinct in the Late Permian after having attained 

 its greatest morphologic development, widest distribution, and greatest 

 number of species and of individuals in that period. 



Nomenclature. — The name Stenoscisma was proposed by Conrad 

 (1839), who designated its type species by monotypy, Terebratula 

 schlotheimi von Buch. He referred to T. schlotheimi as a ". . . common 

 Silurian bivalve," thus introducing an element of confusion that has 

 influenced use of the name Stenoscisma throughout its history. Conrad 

 implied that Stenoscisma was common in the "Silurian" of New York, 

 and Hall (1867) concluded that the species Conrad mistook for T. 

 schlotheimi was the Lower Helderberg species Rhynchonella jormosa. 

 Hall cited an unpublished lithographed plate by Conrad as evidence 

 that Conrad used the name T. schlotheimi for that species. Hall then 

 used Stenocisma (sic) for the group typified by R. jormosa, and sub- 

 sequent authors used the name in the sense that Hall emended it, with 

 several variations in the spelling (e.g. Stenoschisma Hall and Clarke, 

 1894; Stenochisma Grabau and Shimer, 1907; Maynard, 1913, and 

 Kozlowski, 1929). 



King proposed the name Camerophoria in 1844 and 1845, but it re- 

 mained a nomen nudum until 1846 when he designated Terebratula 

 schlotheimi von Buch as the type species. Later in 1846 Herrmannsen 



