INSTITUTE OF SCIENCE, PHILADELPHIA. 133 



Nassa ambigua Montagu var. antillarum Orbigny. 



Biicchmm ambigvum Mtg., Test. Brit., t. 9, fig. 7, 1S03. 



Nassa ambigjia Tryon, Man. iv. p. 42, pi. 13, fig. 194, 1SS2. 



Nassa antillamm Orbigny, Moll. Cuba, ii. p. 141, pi. xxiii. figs. 1-3, 1846. 



Shell Creek and Caloosahatchie Pliocene beds. Recent Florida Keys and 

 ■the Antilles. 



This form is distinguished from the typical N. ambigua by its greater 

 elevation, fewer ribs and sparser .spiral sculpture. It is not very common in 

 the marls. 



Nassa bidentata Emmons. 

 Plate 9, fig. 9. 

 Buccinuni bidentatum Emmons, Rep. N. Car. Geol. Sur., p. 257, fig. 126, 1S58. 



Shell stout, acute, with two smooth nuclear and five subsequent whorls ; 

 transverse sculpture (on the last whorl) of eleven or twelve stout, even, 

 rounded, straight ribs, crossing the whorl, and faint incremental lines; spiral 

 sculpture of (on the upper whorls two) six or seven stout, rounded, continu- 

 ous threads, very slightly swollen as they cross the ribs ; the anterior pair are 

 closer together, the rest equi-distant from each other ; beside these there are 

 five or six close-set threads on the canal ; on the upper whorls two of these 

 threads are visible, and one is included in the suture; suture distinct, not 

 channelled ; terminal varix stout, thick, broader and posteriorly expanded at 

 the suture, overrun by the spirals ; aperture subovate ; pillar-lip callous, with 

 a raised border, smooth, with a sulcus at the posterior commissure of the 

 mouth; outer lip with two strong teeth near the middle, and faint indications 

 of one or two more anterior to the first pair ; canal nearly closed, short, re- 

 curved and twisted; siphonal fasciole strong, the base of the whorl constricted 

 behind it. Max. Ion. of shell 6.5 ; max. lat. 3.75 mm. 



Miocene marls of North Carolina, Emmons. Miocene of New Jersey at 

 Shiloh, Burns. Shell Creek and Caloosahatchie Pliocene beds, abundant. 



Emmons' specimen was not adult, but his figure agrees well with small 

 specimens of the present species. It is not known in the recent state. The 

 specimens vary somewhat in size, and in the closeness of their reticulation, as 

 usual in this genus. 



Nassa Lapenotierei n. s. 

 Plate 9, figure 8. 



Shell small, elevated, slender, with three smooth nuclear and five subse- 

 quent whorls ; transverse sculpture of (on the last whorl ten) elevated, 

 rounded, even ribs with wider interspaces ; more prominent near the suture, 

 but crossing the whorl ; there are also faint incremental striae; spiral sculpt- 

 ure of (on the last whorl seven to nine) little-elevated bands with somewhat 

 wider interspaces, subnodulous at their intersection with the ribs ; between 

 each pair of spiral bands on the last whorl are one to three finer, faint, 



