1911.] NATURAL SCIENCES OF PHILADELPHIA. 347 



This species differs from M. longa chiefly by the shorter, less con- 

 tracted basal portion of the last whorl and the somewhat different 

 sculpture of the interstices between the smooth spiral ribs. , , , 



Mitra sp- undet. PI. XXIV, figs. 7, 8. 



The internal cast of a large Mitre having three columellar plaits, the 

 median one strongest, and with unusually short whorls, contained in 

 the Princeton collection, No. 5,515, is figured (fig. 8). Length of the 

 fragment, which comprises nearly 2 whorls, is 46.5 mm. 



A short piece of the columella of what we take to be the same species, 

 was taken by one of us (fig. 7). It shows three sharp plaits, the middle 

 one largest, and on the wall above the upper plait there are several 

 spiral threads. 



This species is distinct from any known Santo Domingan Mitra. 



MARGINELLID^3. 



Marginella gatunensis n. sp. PI. XXIV, fig. 10. 



A rather small oblong shell, widest at the upper third of the length, 

 the diameter contained about 1.8 times in the length. The spire is 

 conic, short, and so enveloped in callus that the sutures are obliterated. 

 The outer lip is rather broad, thickened outside, incurved, and delicately 

 denticulate within. The nearly straight narrow aperture is rather 

 abruptly but slightly dilated near the lower end. The columella bears 

 four folds, the lower two or three a little flattened towards the outer 

 ends. Upper half of the columellar wall is somewhat calloused, but 

 thin at the outer edge. 



Length 11.5, diam. 6.25 mm. (type). 



" 8.5, " 4.8 " ;if-v1 



This species is clearly distinct from all described from the American 

 Oligocene. It has some resemblance to M. limonensis Dall, of the 

 Costa Rican Miocene (?), but that is more than double the size of the 

 largest M. gatunensis seen, and is relatively narrower. . i ■■ ■ ■ ■ 



Marginella leander n. sp. PI. XXIV, fig. 13. 



The shell is long and narrow, the diameter not quite half the length; 

 approaching a cylindric contour, but tapering a little from the upper 

 fourth to the base; the spire a very short, wide cone, obtuse and 

 rounded at the summit. The aperture is straight, very narrow in the 

 upper moiety, the lower third decidedly wider. Outer lip nearly 

 straight, with narrow, rounded face, thickened externally, a little 

 inflexed in the middle. Columella bearing four rather small folds 

 which run outward upon the ventral face of the shell. There is. a 



