INSTITUTE OF SCIENCE, PHILADELPHIA. 9I 



rather long and narrow ; the outer lip is slightly thickened, but hardly reflected ; 

 behind it there seems to be a sort of varix made by a slight thickening of the 

 shell; the outer lip is internally lirate for a short distance near its edge ; the 

 canal isjshallow and not constricted, it forms no fasciole ; inner lip with a 

 slight glaze. Lon. of the specimen figured 13.O; max. diam. 4.5 mm. 



Pliocene of the Caloosahatchie beds, collected by the writer. 



The specimen has lost the whole of the last whorl except a small triangu- 

 lar piece of the outer lip near the suture. It is probable that the figure repre- 

 sents a longer canal than would have been present if the last whorl had never 

 been formed, judging by the lines of growth on the remaining basal part of 

 the penultimate whorl. 



Family MITRID^. 

 Genus MITRA Lamarck. 

 Mitra lineolata Heilprin. 

 Milra lineolata Heilprin, Trans. Wagner Inst. I. pp. 79, 133, 1887 ; not of Bellardi, 1887. 



Caloosahatchie beds on the Caloosahatchie River and Shell Creek, Florida. 

 Pliocene of South Carolina, one mileeast from Darlington Court House, South 

 Carolina. 



After the examination of a large series, I have come to the conclusion that 

 Prof Heilprin's species is distinct from M. carolinensis Conrad, though that 

 species, which is chiefly Miocene in disti'ibution, is closely related to it. A 

 comparison of the young shows more marked differences than are at first ap- 

 parent in the adult. In carolinensis, about 30 mm. long, the whorls are more 

 distinct, the spiral sculpture rounder and the spirals more numerous, the in- 

 terspaces are more channelled or flat-bottomed, while in lineolata it is rounded 

 concave as if scooped out with a gouge and the spirals are sharp-edged. There 

 are three spirals between the sutures in lineolata and four in carolinensis. The 

 former is also slightly more inflated in the last whorl. In the adults the body 

 of the whorl is usually encircled by five or six fine, distant, sharp threads 

 in lineolata and the pillar is almost perfectly straight; in carolinensis the 

 periphery is usually destitute of sharp threads and the pillar is somewhat 

 twisted, showing a well-marked fasciole. 



The specimen figured by Tuomey & Holmes as carolinensis appears not 

 to belong to lineolata, but we have undoubted lineolata collected by Mr. Frank 

 Burns, of the U. S. Geol. Survey, near Darlington, South Carolina. Specimens 

 reach lOO.o mm. in length. 



M. carolinensis belongs to an older horizon and does not attain so great a 

 size as M. lineolata: the maximum is about 70.0 mm. It is not rare in the 

 Lower Miocene of N. W. Florida, near the Chipola River, and in the Miocene 

 marls of North Carolina. 



M. carolinensis is the type of Conrad's genus Pleioptygma, which he re- 

 ferred to the Volutidce, but which there is no ground, in my opinion, for 

 separating from Mitra. The nucleus is small, shelly, polished and few-whorled. 



