442 TRANSACTIONS OF THE WAGNER FREE 



Dentalium prisma n. s. 

 Plate 15, figure 5. 



Rare in the Pliocene marl of the Caloosahatchie River, Florida, Dall. 



Shell small, stout, not polished, rather acutely pointed behind, four-sided ; 

 the posterior end begins as a four-sided rectangular prism, with one of the 

 sides dorsal, and rapidly enlarges with a moderate arch ; the flat sides soon 

 become impressed so that the angles stand out from them and present the 

 appearance of posts ; tlie interspaces toward the anterior end are a little 

 rounded in the middle line ; the posterior orifice is circular, not sulcate or slit, 

 the anterior one subrectangular ; all the specimens are broken, but the total 

 length of an adult appears to be about 20 to 25 mm. Max. vertical diam. 2.5 ; 

 diam. of posterior end 0.3 mm. 



This species recalls the recent D. platainodcs Watson, from the deep 

 waters of the West Indies, which is, however, rounded when young and more 

 arcuate, while on the sides there is more or less longitudinal striation, the angles 

 are broken up into several threads, and the anterior section by the greater 

 width and medial swelling of the ventral plane is pentagonal and not quadrate. 

 D. Eiig'emilDaW, from the Prairie Creek Eocene, is nearer D. platamodes, having 

 the dorsal plane narrower than the others, but the ventral plane is arched so 

 that the section is keystone-shaped, and the sides are covered with sharp 

 longitudinal striation. 



Dentalium callipeplum Dall. 



D. callipeplum Dall, Rep. Blake Gastr., p. 419, pi. xxvii. fig. 12 b, 1889 ; Bull. U. S. Nat. 

 Mus. No. 37, p. 76, No. 4, plate 27, fig. 12 b, 1S89. 



Pliocene of the Caloosahatchie beds, Dall ; living from South Carolina to 

 Grenada, W. I., in 16 to 175 fathoms. 



A single specimen of this fine shell was found in the marls. 



Dentalium caduloide 11 s. 

 Plate 23, figure 25. 



Chesapeake Miocene of St. Mary's River, near the town of St. Mary's, 

 Maryland, Willcox and Harris. 



Shell small, thin, slightly curved, smooth but not polished, marked only 

 with incremental lines which cross the tube somewhat obliquely ; shell cylin- 

 drical, posterior orifice small, circular, the margin without notch or sulcus, 

 rarely even perceptibly deviating from a circle except when worn or chipped. 

 Lon. of shell 10 to 12 ; max. diam. 1.3 ; min. diam. 0.5 mm. 



This curious little shell is found in large numbers in the St. Mary's marl, 

 and would at once be referred to Cadulus, were it not that there is no trace of 

 a cincrulum, nor any tumidity or compression near the anterior end. Perhaps 

 it should be referred to Siphonodenialmm. 



