I48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 48 



septum high, thin, relatively short on floor but length increasing with 

 height, capped by spoon of camarophorium with unusually broad me- 

 dian projection at anterior edge ; intercamarophorial plate short, may 

 be buried in callus. Muscle marks in camarophorium and pallial marks 

 on floor of valve not observed. 



Table 32. Measurements of selected specimens of Stenoscisma hueconianum from 



locality 712e 



Measurements, in millimeters 



Discussion. — Stenoscisma hueconianum is small for a Permian spe- 

 cies of the genus. It is larger than .S. schlotheimi (Buch) but smaller 

 than 5". venustum (Girty), S. multicostum Stehli, and a large number 

 of undescribed species that I have studied from the Glass Mountains, 

 Tex. In addition, it is smaller than most of the Permian species from 

 the Salt Range, the Urals and Timan, or Timor. 



The stolidium of this species is narrow, and on many specimens it 

 is not preserved. The manner of meeting of the valves indicates that 

 the missing stolidium is not simply a matter of preservation, but that 

 the stolidium never developed on many individuals. 



The species is illustrated as a further example of variation within 

 the genus Stenoscisma. 



Occurrence. — Hueco Limestone, 100 yards W. of USGS Bench 

 Mark 5318, 1.5 miles NNE. of Hueco Inn, Hueco Mountains, Tex. 

 (USNMloc. 712e). 



Age. — Early Permian. 



STENOSCISMA MULTICOSTUM Stehli 



Plate 19, figs. 3-3a 

 Stenoscisma multicosta STEHLI, F. G., 1954, Amer. Mus. Nat. Hist. Bull., vol. 

 105, art. 3, p. 339, pi. 25, figs. 7-9. 



Discussion. — This species is illustrated as an example of a large 

 species whose numerous costae increase in number by bifurcation. It 

 is proportionately wider than S. venustum (Girty) and has more and 

 finer costae. The full breadth of the stolidium of 5". multicostum is un- 

 known, but its extent along the valve edges indicates that it probably is 



