Weller — Kinderhook Faunal Studies. 447 



Park fauna than the last, only two specimens, both of them 

 pedicle valves, having been observed. The species may at 

 once be distinoruished from U. juissouriensis by its less con- 

 vexity, its more obtuse and less incurved beak, its tlatter car- 

 dinal area, its rounded cardinal margins and in the larger 

 number of plications. In these same characters, except the 

 number of plications, the species differs from the allied 

 lamellose, non-punctate, septate Spirifers of the lower Mis- 

 sissippian faunas. 



NUCLEOSPIRA MINIMA n. sp. 



Plate l,figs. 29-30, 



Desci'ijjtion. Shell small, subcircular in outline, lenticu- 

 lar, the two valves subequally convex. Pedicle valve with a 

 narrow, shallow median sinus, a little more gibbous on the 

 umbo than the brachial valve. Brachial valve flattened along 

 the median line and sometimes slightly depressed, but with- 

 out the narrow sinus of the pedicle wave. Surface of both 

 valves marked only by fine concentric lines of growth. 



The dimensions of a pedicle valve of average size are: 

 length 4 mm., width 4.5 mm., convexity 1.5 mm. The larg- 

 est specimen observed has a length of 5 mm. 



Remarks. This species is a close ally of IST. concinna Hall, 

 from the Hamilton fauna of the east, but besides being 

 always much smaller than that species, it has the two valves 

 more nearly equally convex. In none of the Glen Park speci- 

 mens are there any of the fine spines of iV. concinna shown, 

 but their absence may be due to the state of preservation of 

 the shells. 



Seminula sp. undet. 



A small athyroid shell of the type of Seminula occurs in 

 the Glen Park fauna, but all the specimens observed are too 

 imperfectly preserved for identification or description. The 

 specimens vary from 5 to 13 mm. in length, the pedicle valves 

 are usually longer than wide while the brachial valves are more 

 nearly subcircular. 



