24 

 GASTEROPODA. 



Geuus ]S[eritina Laiuarclv. 



Neritina phaseolaris {s}). nov.) — Shell small, obliqael3- snboval; 

 volutious apparently from two and a half to three ami a half, the last 

 one composiug- all bat a very small portion of the whole surface iu sight; 

 aperture obliquel^^ ovate, apparently not crenulated. 



In some specimens, the convexity of the outer volution, from the base 

 of the small elevated fold which is appressed against the spire, to the 

 margin of the aperture, is quite regular, but in others this volution has a 

 revolving, rounded prominence, a little nearer to the suture than the 

 base, which causes a more or less conspicuous flattening at its side as 

 well as a slighter flattening between the prominence and the sutnre. 



Surface marked by moderately distinct lines of growth, and sometimes 

 faint indications of revolving striiie are also seen. 



Greatest diameter of the oval outline of our largest specimen, thirteen 

 millimeters; shorter diameter, ten millimeters; greatest height, lying 

 with its aperture downward upon a table, eight millimeters. 



Fositiou and locality. — Strata of Jurassic age. Salt Creek, near Nephi, 

 Utah, where it is associated with PentacriuKS astenscus Meek and Hay- 

 den. 



Genus Anchura Conrad. 



Anchura nuptialis {sp.nov.) — Shell small ; body subfusiform ; spire 

 moderately prominent, acute, nearly or wholly iucrusted by callus, so 

 that the volutions are obscurely seen except where the callus is exfoli- 

 ated: volutions about seven; revolving angle obscure upon the volutions 

 of the spire, even when bared by exfoliation of the callus, but is more 

 distinct upon the body-whorl, and ends in a slender, falciform prolonga- 

 tion of the lip. This prolongation diverges widely from the axis of the 

 shell, but reaches nearly as far backward as the apex of the spire ; ante- 

 rior borderof the lip with a prominent, rounded lobe, placed just forward 

 of the base of the falciform process, and which is about as wide as that 

 process is at its base ; from this lobe, the border of the lip passes for- 

 ward with a concave cnrve to the base of, and ends in, the long, slender, 

 anterior canal. Aperture unknown. 



Length from the apex of the spire to the end of the anterior canal, 

 twenty millimeters; width, measuring across from the base of the 

 falciform process of the lip, nine millimeters: spire, falciform process, 

 and anterior canal, each about seven millimeters. 



Position and locality. — Strata probably of Jurassic age, fifty miles 

 north of Camp A})ache, and five miles west of Mineral Spring, Arizona. 



CRETACEOUS PERIOD. 



CONCHIFERA. 

 Genus Pinna Linna-us. 



Pinna petrina {sp. nov.) — Shell moderately large, broad, rather thick 

 for a species of this genus, rapidly expanding in height as it increases in 

 length ; dorsal margin concave; ventral margin convex ; a more or less 



