NO. 2023. A BRACKISH WATER PLIOCENE FAUNA— DALL. 233 



ovately rounded and sculptured only by incremental lines, though in 

 young specimens there is sometimes a series of fine spiral grooves near 

 the canal. Aperture narrowly ovate, acute behind; outer lip flexu- 

 ous, sharp, produced in front, smooth inside; pillar arcuate, smooth, 

 with a thick layer of enamel extending over the body; suture dis- 

 tinct, not appressed. Length (slightly decollate), 20; maximum 

 diameter, 9.5 mm. Length of figured specimen, 16 mm. 



Station 6040 near Alexandria, Louisiana; also from station 6445, 

 the Producer's Oil Co.'s well. Pine Prairie oil field, at a depth of 1,540 

 feet, Louisiana, Matson; and at station 6440, Texas. Type, U. S. 

 Nat. Mus., No. 166298. 



This is a form of rather unusual characters for the genus, but one of 

 somewhat similar aspect among recent shells has recently been de- 

 scribed by Doctor Pilsbry from Mexico. 



TURRITELLA SATILLA, new species. 

 Plate 22, fig. 6. 



Shell of 10 or more whorls, small, acute, fragile, with a minute 

 smooth nucleus of 2 or 3 whorls; suture deep, distinct; spiral sculpture 

 on the subsequent whorls of 3 prominent more or less beaded elevated 

 threads or cords, with one or more simple mmute threads in the wider 

 interspaces; axial sculpture of incremental flexuous lines which, 

 when strong, cut the major spirals into beads or nodules; base bor- 

 dered by major cord, within w^liich it is slightly concave and smooth; 

 aperture subquadrate and simple. Length of type-specimen, 4.5; 

 maximum diameter of base, 1.5 mm. 



Station 6040, near Alexandria, Louisiana. Type, U. S. Nat. Mus., 

 No. 166300. 



Though so small a shell, this species possesses all the usual charac- 

 ters of the genus, and may grow to a much larger size. 



ISAPIS OBSOLETA, new species. 

 Plate 22, fig. 8. 



Shell small, with an acute spire and slightly turrited whorls; last 

 whorls much the largest, ovate, spirally sculptured with 7 channeled 

 grooves crossed by prominent lines of growth visible only in the 

 grooves; interspaces smooth except for faint incremental lines; 

 aperture ovate, outer lip sharp, simple; pillar arcuate, with a narrow 

 umbilical chink behind it; nucleus lost. Length of shell, 3.5; diame- 

 ter, 2.5 mm. 



Station 6040, near Alexandria, Louisiana. Type, U. S. Nat. Mus., 

 No. 166301. 



A very distinct species of a genus which contains but a few species 

 on the American coast. 



