DESCRIPTIONS OF SPECIES. 187 



graduall)' rounded; in the young, however, they are acute. On the faces 

 are two strong elevated tubercles; between these there may be developed a 

 third, but not so large, and there may be developed two other rather small 

 tubercles, one on the outside of each large tubercle. Surface granulate; 

 there are often strise running upward from the basal portion. Wall thick, 

 vesiculated, perforated. Septa in five cycles, those of the fifth fusing in 

 front of those of the fourtli; faces granulate. Columella very vesiculate, 

 elongated in the longer transverse axis of the calice. The size of the species 

 is indicated in the figures. 



Localities. — Alabama, Mississippi, Louisiana, and Texas; 4 miles north- 

 east of Quitman, Clarke County, Mississippi; 8 miles west of Enterprise, 

 Clarke County, Mississippi; Wautubbee Hills, Mississippi; 12 miles north- 

 west of Enterprise, Clarke County, Mississippi; 1 mile south of Hickory, 

 Mississippi; 2 miles southeast of Hickory, Mississippi; Moodys Branch, 

 Jackson, Mississippi; Claiborne, Alabama; Holstuu's well, Louisiana; sec. 

 17, T. 18 N., R. 6 W., Bienville Parish, Louisiana; Pittman's mill, SW. ^ 

 of SE. 4 of sec. 19, T. 19 N., R 7 W., Claiborne Parish, Louisiana; St. 

 Maurice, Louisiana; Montgomery, Louisiana (several specimens of var. 

 triangidare Con.; one specimen has a small amount of pellicular epitheca 

 on the base); Mount Lebanon, Louisiana; 1 mile below Shipps Ford, 

 Bastrop County, Texas; Elm Creek, Lee County, Texas; Alabama Bluff, 

 Trinity River, Houston County, Texas. 



There is in the collection of the Academy of Natural Sciences of Phila- 

 delphia a specimen of Endopachys from New Jersey (Shark River beds). 

 This is probably E. maclurii, but the specimen is too poor for positive 



identification. 



Geologic occurrence. — Froui tlic Lowcr Claibomc to the Jacksonian stage, 



inclusive. 



This is a protean species, and it is very difficult to characterize it so as 

 to include all of the variations to which it is susceptible. 



There is in my collection from Mount Lebanon, Louisiana (PI. XXII, 

 fig. 1), a specimen that diff"ers from the usual forms of J^. maclurii. Its 

 margins are nmch compressed, form subtriangular, wall rather solid, but 

 perforate, distinct costaj present. This is apparently only a varietal form 

 of i'. maclurii. 



