374 PROCEEDINGS OF THE ACADEMY OF [PaRT II 



tural cingulus. It is this stage which Miss Maury described as P. 

 ormei. The longitudinal sulcations disappear on the last two or 

 three whorls, which are not granose. The base has several shallow 

 spiral grooves. 



Length 29.5, diam. 17.3 mm.; 5 whorls remaining. 



Type and 13 others no. 2600 A. N. S. P. 



All of the 14 specimens have been more or less rolled and worn, 

 probably indicating that we have to do with an estuarine snail wdiich 

 had been washed out into the beds of marine deposition. 



Potamides roumaini Pils. (Proc. A. N. S. Phila., 1910, p. 487, from 

 between Las Caobas and Hinche, Haiti, W. W. Webster and Ed- 

 mond Roumain) is a smaller and narrower species than P. supra- 

 sulcatus, with stronger spiral sculpture. Length 24, diam. 13 mm. 

 Type no. 1314 A.N. S. P. 



Potamides caobasensis Pilsbry. 



Potamides caobasensis Pils. Proc. A. N. S. Phila. 1910, p. 488. 

 The shell is smooth, the whorls prominent below the suture. Length 

 (broken) 23 mm. Type no. 2603 A. N. S. P. Not collected by Gabb. 



Potamides dentilabris (Gabb) Plate XXIX, figs. 6, 7. 



Cerithiurn dentilabre Gabb, Tr. Am. Philos. Soc, xv, 1873, p. 237. 



This shell resembles the East Indian P. -palusti'is (L.). There are 

 four spiral cords about equal to their intervals running over small 

 axial folds and an occasional rounded varix about double the size 

 of the folds. Coincident with the varices, two lip-teeth are formed 

 internally, and there is also a callous fold on the parietal wall. Col- 

 umella has a strong oblique plait. Probably none of this armature 

 would be visible in an entire adult shell, but it is exposed in the 

 fossils, most of which are broken back to the last varix. All have 

 been rolled, and probably were washed out of a lagoon or estuary. 



Length 49.5, diam. 21 mm.; 8 whorls remaining. 



Type and six other specimens no. 2502 A. N. S. P. 



Potamides gastrodon Pils. and Johns. Plate XXXI J, figs. 5, 6. 



Proc. A. N. S. Phila., 1917, p. 171. 



This species differs from P. transecta Dall, of the Tampa Silex bed, 

 in details of sculpture, having three instead of four main spirals on 

 each whorl, nodules at the intersections of the axial riblets, and a 

 very prominent varix on the left of the last whorl. The type has 

 a weak thread dividing the spiral interstices on the last whorl. In 

 other specimens of the lot these secondary spirals are well developed. 



