TEAvEs.] LARAMIE AND CRETArEOU.s I.WERTEBRATA. 57 



CrEXELLA (?) PARVCLA. (X. Sp.) 



Plate 9, li-. 1. 



Shell small foi- the ii-enu>. (£i--iimiiiu- it tri )x' a i~'reaella) apparently 

 not exceedini;- a quarter <,if an inch in length by one-third le^s in height, 

 moderatelv inflated but very tumid in the umbonal re^-ion, lateral 

 outline tranver-ely elliptic subovate, very narrrjw at the anterior end 

 and increasing rapidly in breadth, .>r rather in height, to the posterior. 

 Anterior side extremely .small, its margin subtruncated almost verti- 

 cally under the beaks: posterior side much longer and broader, its 

 extremity regularly rounded. Beaks anterior, terminal and recurved. 



Surface nearly smooth and marked only with very fine and clo-e >ei 

 concentric -tria=', which are not visible without the use of a lens. 

 Characters of the interior of the valves unknown. 



Length of the largest specimen collected, six millimetres ; maximum 

 height of the -ame. four mm. ; exact thickness through the closed 

 valves not ascertainable with much accuracy. 



llilkEiverEidge. E. G. ;McConnell, lsS2: three perfect single valves, 

 with the test preserved on each. 



It is possible that this little shell shou Id be placed in Conrad's geaus 

 -ircoy-er/iir'' rather than in Crenello. If radiating stria- or custie or a 

 cancellate sculpture are essential cliaraoters of the latter genus, then 

 it is clear that the present shell cannot be a Crenella. The only Xorth 

 American species to which the C. (?) parcula bears much resemblance 

 is the Jlodi'ola 'jranulato--:ostellafa of Ecemer,t from the Texan Creta- 

 i.eous. but this latter shell, as its specific name implies, has the oitter 

 sui'face of the valves marked with numerous, equal and granulated, 

 radiating lines. Judging by the published figures, the Cretiella 

 deijantiila of 3Ieek and Hayden, j from the Fox HilK G-ro up of Deer 

 Creek and the Yellowstone Eiver, is as broad or high anteriorly as it 

 is posteriorly, and its surface is said to be marked with bifurcating 

 radiating stri:e. 



* Am. .Journ. Conch., vol. I., p- UO. pi. 10, ht'. 14. 

 tDie Kreidcbildungen von Texas, p. .54, pi. 7. f\gi. VI a. b, o. 



X Meek. 1876. Kep. U.S. Gel. Suit. Terr., vol. IX., Rep. Invert, Cret and Tert. Fu.^s. 0. 

 Mis.?. Cy., p. 75, pi. 28, figs. 6, a, b, e 



