BuLIvETIN 39 



Area cadida Shelton, 1916, Palaeont. Amer. , No. i, p. 16, pi. 3, figs. 

 II, 12. 



We have several small valves of a Calloarca from the Mio- 

 cene limestones of Port Limon, the largest of which has a length 

 of 18 mm. They belong to the Area eandida group and may 

 possibly represent the young of that species. They seem to dif- 

 fer in being more finely sculptured, especially about the middle 

 of the shell disk. This sculpture consists of fine, beaded or 

 granulated radial threads, which become coarser on the anterior 

 and posterior submargins. 



The Area Candida is recorded by Dall from the Bowden beds 

 of Jamaica, the equivalent of the coral limestones of Limon. Dall 

 also mentions from the same locality, the occurrence of a smaller 

 and possible distinct species. The Area eandida is a common re- 

 cent species of the West Indies and the Caribbean, and is abund- 

 ant on the north coast of Panama and Costa Rica. 



Length 18, height 11?, semidiameter 3.75 mm. 

 Gatun Stage: Port Limon. 



Subgenus SCAPHARCA Gray 

 Area dariensis Brown and Pilsbry Plate 22, figures 10-13 



Area oronlensis Dall, 1898, Trans. Wagner Free Inst. Sci., vol., 3, pt. 



4, p. 658. Not of Gabb. 

 Area dariensis Brown and Pilsbry, 1911, Proc. Acad. Nat. Sci. Phila., 



vol. 63, p. 362, pi. 22, fig. 10. 

 Area gatunensis TomIq., Dec. 191 1, Jahrb. der K-K Geol. Reichsanstalt, 



vol. 61, p. 493, pi. 30, fig. 4. 



The common Ark of the Canal Zone. The shell is elongate 

 in form with about 30 ribs. The ribs of the left valve are usually 

 granulated over the whole shell, while those of the right valve 

 are narrow and smooth on the middle of the shell disk. The ribs 

 are characteristically divided on the anterior and posterior ends 

 of the shell. 



Gabb has described an Area oro7ilensis from the black shales 



