Amkeican East Coast Akcas 



connected with the external sculpture, but form long, even ridges on the thick margin. 

 Specimens labelled from Paumotus and from the Mediterranean which are evidently 

 A. divaricata are thin and the sculpture of the posterior part is conspicuously different 

 from that of the rest of the shell, the ribs there are fewer than in the other forms, more 

 conspicuously diverging and are much stronger than the concentric sculpture. The pos- 

 terior ribs rise along the umbonal ridge. The crenulations of the posterior margin are 

 larger to correspond with the larger posterior ribs and a secondary set of fine wrinkles 

 overruns the main crenulations. 



Amr reticulata is characterized by its small, nearly white, well-sculptured shell, con- 

 centric ridges and posterior ribs rising along the umbonal ridge. The teeth are grooved 

 at the sides and man}' of them are v-shaped. The name dathrata was used by Defrance 

 {1816), M'Coy and Reeve, squamosa by de Koninck (1842), and reticulata by M'Coy 

 (1844). Navicula aspersa Conrad is this species, not the young of A. cuculloidcs. 



Dimensions. — Large shell. Ion. -1-10,-17.5; alt. -1-3,-13; diam. 15 mm. 



Occurrence. — Eocene of the Jacksonian at Moodj-'s Branch, Jackson, Mississippi; 

 Oligocene of the Bowden beds, Jamaica; Matura, Trinidad; of the Tampa silex beds at 

 Ballast Point, Florida, and on the Chipola River, Pliocene of Limon, Costa Rica, and 

 of the Caloosahatchie marls ; Pleistocene of the Antilles generally ; and recent from Cape 

 Hatteras to Barbados and the Gulf of Campeachy. — Dall. Recent from Trinidad, 

 Cuba, Panama, Paumotus and the Mediterranean. — C. U. Museum. 



Area millifila Dall 



Plate IV, Figures 13, 14 

 Area [Acar) millifila Dall, Wagner Free Inst. Sci., Trans., vol. 3, pt. 6, pi. 56, figs. 21, 24, 1903. 



"Pliocene marl of Shell Creek, Florida; the ligament is typical of Acar, the radial 

 threads are minutely granular, especially on the posterior dorsal slope; the shell is thin 

 and the scars obscure." — Dall, 1903. 



Area Harris! (new name) 



Plate IV, Figure 15 



Area inornala Meyer, Geol. Surv. .-Ma , Bull i, p. 79, pi. i, fig. 24, 1886. 



Area inoruala deGregorio, Faune Eoc^nique de I'Alabama, p. 197, pi. 24, fig. 29, 1890. 



Area {Fossularcaf) inoiiiata Dall, Wagner Free Inst. Sci., Trans., vol. 3, pt. 4, p. 658, 1S9S. 



Not Area {Cucullcea) inornata Meek and Hayden, Acad. Nat. Sci. Phila., Proc. for 1S58, p. 51, 1858. 



"Trapezoidal; anterior side truncated, flat; beak small; ligament area verj' low ; 

 teeth smallest toward the middle; covered with indistinct concentric lines; margin entire. 



"Resembles Atxa Icevigata, Caillat, from the Paris basin, but is less oblong." — Meyer, 

 1886. 



From the descriptions this species appears to be nearest Fossularca. The name inor- 

 nata is preoccupied by Meek and Hayden. Their species, from the Black Hills, has been 

 placed in Gratnmalodon. Meyer's species is renamed in honor of Professor G. D. Harris 

 for his work on the Eocene. 



Occurrence. — Eocene of Claiborne, Alabama. — Meyer. 



