124 BuivivETiN 39 296 



difference between losquemadica and a7nbigua, lies in the proto- 

 conch, which in typical ambigtca is short and blunt, but pointed 

 and composed of several whorls in losquemadica. Our shells are 

 larger than typical losquemadica from Santo Domingo, 

 Height 11.50, diameter 7.00 mm. 

 Gatun Stage: Port Limon. 



Coll. 7, Estrella River. 



Aleclricn meresida, n. sp. Plate 9, figure 19 



Shell small, a large body whorl and a sharp pointed spire; 

 nucleus of 2 small, convex whorls followed by 5 post-nuclear 

 whorls; sutures distinct but not excavated; the sculpture con- 

 sists of about 1 2 ribs which are variable in their strength and 

 spacing; the ribs are crossed by subequal spiral cords separated by 

 wide, interspaces in which there may appear a smaller intermed- 

 iate spiral; the suture is bordered by a set of 2 or 3 finer spirals; 

 there are 3 spirals on the spire-whorls and 8 on the last whorl 

 above the contracted zone of the canal; aperture subcircular with 

 a thick, heavy outer lip. 



Height 7, diameter 4.5 mm. 



The aperture is completely filled with a hard matrix which 

 completely conceals the characters of the inner and outer lips. 



Uscari Stage: Old Man Sam Creek. 



Genus NORTH! A Gray 



Northia northiae Gray, var. piocenica, n. var. Plate 9, figuies 7, 14 



cf. Northia northice Gray, 1834, in Griffith's Cuvier, pi. 30, fig. 2. 

 cf. Northia northia: Kiener, 1832 Icon., Bticcinum , p. 23, pi. 9, fig. 



28. 



The Northia northicB Gray, (iV". serrata Dufresne) is a 

 common and characteristic West Coast or Pacific species, ranging 

 from the Ba}^ of Panana to Guayaquil Ecuador. The fossils rep- 

 resented by three incomplete specimens differ only from recent 

 examples from Panama in lacking the hump-like thickening in 



