1911.] NATURAL SCIENCES OF PHILADELPHIA. 345 



This appears to be a rather abundant shell at Gatun, but only one 

 out of ten specimens retains the long anterior canal entire. It is 

 extremely like Fusinus in contour, and is more nearly related to 

 D. fusifonnis than to other species known to us. 

 Drillia zooki n. sp. PI. XXIII, fig. 8. 



A species very closely related to D. fusiformis Gabb, of the Santo 

 Domingan Oligocene, but differing as follows: The anterior canal is 

 much shorter. There is no cord at the lower edge of the sutural 

 fasciole, above the supraperipheral cord. There are eleven somewhat 

 protractive longitudinal folds on the last whorl, which are narrower 

 than in D. fusiformis. In other respects the two species seem to be 

 substantially alike. 



Length of last 4 whorls 20.5, diam. 8.5 mm. 



Only imperfect specimens were collected. Named for Mr. E. Zook, 

 of the Panama R. R. 



Drillia oonsors (Sowerby). 



Pleurotoma consors Sowb., Journ. Geol. Soc. Lond., VI, p. 50. 



The Gatun specimens seem to have a slightly longer anterior canal 

 than those from Santo Domingo. 



♦Pleurotoma gertrudis Toula. 



Pleurotoma (Genota) gertrudis Toula, Jahrb., p. 709, fig. 9. 



Cythara heptagona (Uabb). 



Mangelia heptagona Gabb, Geol. Santo Domingo, p. 211. 



One typical specimen. 



CANCELLARIID^. 

 Cancellaria dariena Toula. PI. XXIV. figs. 3, 4. 



C. dariena Toula, Jahrb., p. 703, PI. 25, fig. 13; PI. 28, fig. 2. 



This species resembles C. reticulata very closely, yet differs by having 

 a much larger embryonic shell which is also more globose, of three 

 whorls. There are about 5h post-embryonic sculptured whorls, 

 while in reticulata there is at least one whorl more in shells of the same 

 size. The first sculptured whorl in C. dariena has five spiral cords and 

 10 or 1 1 massive longitudinal folds. On the last whorl there are usually 

 some smaller threads in the intervals between the principal spirals, 

 above the periphery. The aperture is very much like that of C. reticu- 

 lata except that a thin callus spreads far forward over the whorl to 

 the middle of its ventral face. 



Length 30, diam. 16.5 mm. 



A form which may be called Cancellaria dariena trachyostraca, 

 23 



