344 PROCEEDINGS OF THE ACADEMY OF [April, 



Drillia gatunensis Toula. 



D. gatunensis Toula, Jahrb., p. 707, PI. 25, fig. 16. 



Related to D. indentata J. and P., of the Santo Domingo Oligocene, 

 but it differs by having more numerous spirals. In this feature there 

 is rather wide variation, many specimens having but four wider spiral 

 cords on the whorls of the spire below the sutural fasciole. It attains 

 a length of 40 mm. 



Drillia isthmica n. sp. PI. XXIII, figs. 10, 11. 



A small species, related to D. jparkeri Gabb of the Santo Domingo 

 Oligocene, 2\ or 3 smooth whorls compose the embryonic shell, which 

 is somewhat worn. Succeeding whorls have a distinct, narrow, 

 convex, sutural fasciole, undulating in conformity with the suture, 

 and rather weakly plicate, the plicse perceptibly retractive, unevenly 

 developed. Below the fasciole there are broad folds, subacute at 

 their summits. On the slopes of the folds there are some protractive 

 wrinkles, like ripples upon waves. There is an interrupted spiral 

 groove midway between sutures, appearing as a series of short strokes 

 in the troughs of the waves only. The aperture is imperfect in the 

 type specimens. There is a small callous nodule on the left side of 

 the posterior sinus. 



Length 13 mm., 11 whorls. 



The absence of spiral striation makes this species quite distinct 

 from others of the Isthmian beds. 



Drillia fusinus n. sp. PL XXIII, fig. 7. 



The shell is fusiform, widest at the middle, like a slender Fusinus 

 (Fusus). Spire attenuated towards the small, obtuse apex. The 

 first half whorl is rounded, uptilted; then an acute carina appears at 

 the lower third, at the end of the first whorl a second small cord appears 

 above the suture. Beginning with the third whorl a small thread 

 appears on the upper side of the main carina, and low longitudinal 

 folds begin. On subsequent whorls these folds continue to the penulti- 

 mate. They are low, very wide and on the last whorl subobsolete. 

 The penultimate whorl has four subacute main spirals, one subsutural, 

 two peripheral and one suprasutural; the intervals bearing smaller 

 spiral threads and striae. The last whorl has many spiral cords and 

 threads. Whorls 12, concave above, the last one swollen in the middle, 

 concave and extended in a long, straight anterior canal. Aperture 

 narrow, small, less than half as long as the anterior canal, not deeply 

 sinuated above. 



Length 40, diam. 12 mm. 



