1917.] NATURAL SCIENCES OF PHILADELPHIA. 175 



smooth base. There are nineteen ribs on the penult whorl. Aper- 

 ture somewhat trapezoidal, the columella slightly sinuous, thickened. 



Length 3.8, diam. 1, length of aperture 0.75 mm. ; 8 post-embryonic 

 whorls. 



Type No. 3026, A. N. S. P. 



Turbonilla (Pyrgiscusi santodomingensis n. sp. 



The shell tapers very slowly. Nuclear and early neanic whorls 

 wanting. The rest have rather strong, rounded, straight vertical 

 ribs, which become slightly retractive on the last two whorls, and 

 part of them continue very weakly over the base. There are 17 ribs 

 on the penult whorl. There are five (5) spiral impressed lines between 

 sutures, not crossing the summits of the ribs. On the base there are 

 about 6 spiral impressed lines, the lower three continuous. The 

 aperture is especially short; columella very strongly folded and 

 thickened. 



Length 6.4, diam. 1.35 mm.; 10| whorls remaining. 



Type No. 3034, A. N. S. P. 



Longer, more slender than T. dominicensis, with fewer ribs and 

 fewer spirals which are more deeply impressed. It differs more 

 fundamentally by the very strong columellar fold. 



Turbonilla (Chemnitzia) galeata n. sp. 



The shell is very slender, with a large helicoid nucleus; next whorl 

 sculptured with numerous ribs, subsequent whorls with fewer vertical 

 rounded ribs running from suture to suture, nearly as wide as the 

 concave intervals, which under a high power show a faint woven 

 texture. Sixteen ribs are on the penult whorl. On the last whorl 

 there is an inconspicuous spiral depression at the anterior termination 

 of the ribs. The base has some faint spiral impressed lines. The 

 aperture is ovate; columella somewhat thickened, distinctly folded 

 above. 



Length 2.9, diam. 0.55, length of aperture 0.4 mm.; 1\ post-nuclear 

 whorls. 



Type No. 3028, A. N. S. P. 



Turbonilla (Chemnitzia) peraequa n- sp. 



Embryonic whorls helicoid. Subsequent whorls with sculpture 

 of numerous rounded vertical ribs equal to the concave intervals, 

 both ribs becoming weaker and terminating a little distance short 

 of the lower suture; the concave intervals also terminating there, 

 but rather abruptly. There are 22 ribs on the penult whorl. Base 

 smooth. 



