MARYLAND GEOLOGICAL SURVEY 191 



? Tritiaaraia Meek, 1864, Miocene Check List, 8mitb. Misc. Coll. (183), p. 20. 

 Ptychosalpinx porcina Gill, 1807, Amer. Jour. Conch., vol. iii, p. 154. 

 PlychoHalpinx ( Paranassa) porcina Conrad, 1868, Amer. Jour. Conch., vol. iii, p. 262. 

 V Ptychonalpinx ( Pararutsita) arata Conrad, 186S, Amer. Jour. Conch., vol. iii, p. 202. 

 Ilyanasaa iParanansa) porcina Dall, 1892, Trans. VVaj^ner Free Inst. Sci., vol. iii, 

 pt. ii, p. 238. 



Description. — " Subovate, acute, slightly undulated, and spirally 

 striated; labrum toothed. 



" Shell with numerous, subequal, slight undulations, disappearing on 

 the body whorl, and about seventeen transverse, little elevated stria? : 

 whorls nearly six, but little convex : suture very narrow, consisting of a 

 mere indented line : apex acute : aperture moderate, rather more than 

 half the length of the shell: labium covering the columella, concave: 

 labrum not thickened; on the inner submargin with striaBform teeth. 



"Length one inch and a quarter, breadth rather more than three- 

 fourths of an inch. 



" This is shorter than the reticosum of Sowerby, the suture is not so 

 deeply impressed, the undulations are not so obvious, and the concavity 

 of the labium is much more profound." Say, 1824. 



Say and Dall are the only ones who have recorded porcina or arata 

 from Maryland, and Dall gave them on the authority of Say. It is of 

 course possible that Finch found them while all later collectors have 

 missed them. But considering the amount of material collected since 

 then, it seems more probable either that Finch's specimens (of these 

 species) came from Virginia, or that Say's figures are extremely bad 

 representations of aberrant forms of the species here and by Dall re- 

 ferred to Ptychosalpinx altilis Conrad. Say's figure of arata is extremely 

 bad in any case, and because of this reason and of the possibilities stated 

 above, the references to arata are with query grouped in the above s}!!- 

 onomy under porcina. 



Occurrence. — St. Marys Formation. St. Mary's Eiver(?). 



Family NASSID/E. 



Genus NASSA Lamarck. 



Nassa calvertensis n. sp. 

 Plate XLIX, Fig. 1. 



Description. — Shell short, globose, six-whorled; body whorl large, 

 rotund, or with a subangular shoulder; about 2.5 closely-set raised re- 



