76 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



POLYSTOMELLA MACELLA (Fichtel and Moll). 



Plate 27, figs, la, 6. 



Nautilus macellus, var. a, Fichtel and Moll, Test. Micr., 1803, p. 66, pi. 10, 



figs. e-g. 

 Polystomella macella Parker and Jones, Ann. Mag. Nat. Hist., ser. 3, vol. 5, 



I860, p. 104, No. 8.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 



1884, p. 737, pi. 110, figs. 8, 9, 11. 



Description. — Test compressed, bilaterally symmetrical, peripheral 

 margin acute, somewhat carinate, not lobulated, sixteen to twenty 

 chambers in the last formed coil; reticulated bridgings occupying a 

 greater area than the intermediate portions ; umbilical region slightly 

 depressed, with a few large pores; aperture a curved or V-shaped 

 slit at the base of the apertural face, either simple or divided into 

 secondary openings. 



Diameter, 0.75 mm. Cat. Nos. 324689-90, U.S.N.M. 



Specimens were obtained from two stations in the Emperador 

 limestone, as follows: U.S.G.S. 6015, from cream-colored coral lime- 

 stone, old quarry one-quarter mile north of west from Empire ; and 

 6016, one-third mile north of west of the same place. 



POLYSTOMELLA CRISPA (Linnaeus). 



Plate 27, figs. 2a, o. 



" Cornu Hammonis orbiculatuni " Plancus, Ooncfi. Min., 1739, p. 10, pi. 1, 



fig. 2. 

 Nautilus crispus Linnaeus, Syst. Nat., ed* 12, 1767, p. 1162. 

 Polystomella crispa Lamarck, Anim. sans Vert., vol. 7, 1822, p. 625, No. 1. — 



d'Orbigny, Forarn. Foss. Bass. Tert. Vienne, 1846, p. 125, pi. 6, figs. 9- 



14.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 736, 



pi. 110, figs. 6, 7. 



Description. — Test bilaterally symmetrical, much compressed, pe- 

 ripheral margin obtusely angled; umbilical region not depressed; 

 chambers numerous, eighteen to twenty chambers in the last formed 

 coil, sutures indistinct, bridging wider than the intermediate clear 

 space; margin not lobulated; umbilical region umbonate, filled with 

 clear shell material, often with a few pores; aperture a narrow slit 

 at the base of the apertural face of the chamber, usually showing 

 more or less division into secondary openings. 



Diameter, up to 1.25 mm. Cat. No. 324691, U.S.N.M. 



Specimens referable to this species were obtained from the Gatun 

 formation at U.S.G.S. No. 60295, one-fourth to one-half mile north 

 of Camp Cotton on relocated line of the Panama Railroad, indurated 

 argillaceous and sandy marl. 



