BRACHIOPODS. ' 87 



Horizon and localities. Lower Carboniferous, Kinder- 

 hook limestone: Clarksville (Pike county). 



Syringothyris carteri ( HALL). 



Plate xl, fig. 10. 



Spirifer carteri Hall, ]857 : lenth Rep. New York State Cab. Nat. Hist., 



p. 170. 

 Spirifer (Cyrtia) hannibalensis Swallow, 1860: Trans. St. Louis Acad. 8ci., 



vol. 1, p. 647. 



Syringothyris typo. WiLchell, 1863 : Proc. Acad. Nat. Sci., Phila., p. 7. 

 Syringothyris typa Winchell, 1870: Proc. Am. Philos. Soc., vol. XLI, p. 



252. 

 Syringothyris cuspidatus Herrick, 1888 : Bui. Dennison Univ. , vol. Ill, p. 



41. pi. i, fig. 7. 

 Syringcthyris carteri Schuchert, 1890: Ninth Ann. Rep. State Geologist 



New York, p. 30. 



Shell attaining a rather large size, very thin, nearly semi- 

 circular, as seen in a direct view from above or below, and 

 rhombic-subquadrangular in a front or posterior view, with 

 length generally a little more than half the breadth, and the 

 breadth usually about twice the height of the area ; hinge-line 

 about equaling the greatest breadth ; front and lateral margins 

 forming together a more or less nearly semi- circular curve, or 

 with the central part of the former sometimes a little straight- 

 ened, or even very faintly sinuous in outline, and the latter 

 meeting the hinge at rather less than right angles behind. 

 Dorsal valve moderately convex in the central region, thence 

 sloping laterally and rounding more abruptly to the beak and 

 anterior lateral margins than to the middle of the front ; mesial 

 fold depressed, smoothly rounded, equaling about two-thirds 

 the breadth of the valves at the front, and sometimes showing 

 on internal casts a faint linear mesial impression ; beak small, 

 and with the very narrow area incurved. 



Ventral valve much elevated at the beak, thence sloping 

 laterally, with slightly convex outlines, at an angle of 100 to 

 125, and more abruptly to the front and anterior lateral mar- 

 gins ; mesial sinus smoothly rounded within, rather shallow or 

 moderately deep anteriorly, where it terminates in a short, 

 rounded projection fitting into a corresponding sinus in the 

 margin of the other valve ; beak elevated, obtusely angular and 



