Weller — Kinderhook Fauna' Studies. 201 



coiled upon each other at the base of the band. Angle of 

 the spire seventy to eighty degrees. Surface characters un- 

 known. The nature of the imbedding material is such that it 

 has entirely destroyed the surface markings; but the form of 

 the shell is so entirely different from any other described 

 from rocks of the same age that it is easily recognized." 



The dimensions of the type specimen are: total height 

 about 43 mm., greatest dimensions of the last whorl 40 mm. 



Remarks. This species resembles P. tabulata from the 

 Coal measures more closely than any other. De Koninck has 

 made this last species one of the typical ones of his genus 

 Worthenia * and as P. mississippiensis is probably cogeneric 

 with P. tabulata it is here placed in the genus Worthe- 

 nia. Whitfield has made P. textiligera a synonym of this 

 species, but this is certainly a mistake. 



Capulus paralius ( W. W. ). 



PI. XX. f. 13-14. 



Original description. " Shell rather below the medium 

 size, composed of but little more than one loosely-coiled 

 volution. Apex minute, laterally compressed ; the upper half 

 of the shell somewhat angular on the dorsum, more rapidly 

 expanding and less angular in the outer part. Body of the 

 shell marked by several proportionally strong, irregular plica- 

 tions, which give a deeply undulating or dentate character to 

 the margin of the aperture. General form of the aperture 

 irregular ovate. Peristome much prolonged on the anterior 

 portion, and a little more expanded on the right side." 



" Surface marked by strong concentric lamellose lines of 

 growth, which are strongly undulated as they cross the pli- 

 cations." 



The dimensions of the type specimen are : depth of aper- 

 ture 14 mm., width of aperture 13 mm., and height of shell 

 from the plane of the aperture 13 mm. 



Remarks. The specimen represented by figure 13 is des- 

 ignated as the type of this species in the University of Mich- 

 igan collection, the specimen represented by figure 14 being 

 designated as a variety of the species. 



* Faun, du Calc. Carb. Bele. 4 : 64. 



