1921] NATURAL SCIENCES OF PHILADELPHIA. 363 



which are not known to be represented in the Santo Domingo beds. 

 Phaliinn, in a sHghtly generahzed form, was ah-eady well developed 

 at the dawn of the American marine Eocene as now known ; and the 

 differentiation of the main groups of Cassididae apparently took 

 place earlier. 



Morum domingense (Sowerby) 



Oniscia domingensis Sowerby, Q. J. Geol. Soc, vi, 1849, p. 47, pi. 10, fig. 3. 

 Morum domingensis Sowb., tiabb, Tr. Am. Philos. Soc, xv, 1873, p. 223. 



This species is closely related to Morum harpula (Conr.), of the 

 Vicksburg Oligocene, but it differs by having the expanded callus 

 of the ventral side much less coarsely granulose, and only the peri- 

 pheral row of sharp tubercles appears upon the whorls of the spire. 

 In M. harpula two such rows are visible. 



Length 36, diam. 22.3 mm. 



DOLIIDAE. 



Malea camura Guppy. 



Malea camura Guppy, Quart. .Journ. Geol. Soc, xxii 1866, p. 287, pi. 17, fig. 9. 

 Malea ringens Gabb, Tr. Am. Philos. Soc, xv, p. 223. 



This is apparently distinct specifically from M. ringens, now liv- 

 ing on the Pacific coast of Central America and Mexico; but camura 

 undoubtedly is ancestral to the living form. The difference is more 

 noticeable in the younger than in the adult individuals. In M. 

 camura the lip is less expanded and flattened, and has a uniform 

 slope toward the interior. The callous projection on the parietal 

 wall is always bilobed, not trilobed as in ringens; the columellar 

 prominence consists of a large bifurcate tooth with a smaller one 

 below it, the latter usually destinctly separated from the former. 



Guppy 's type is a young shell, but all of the Jamaica specimens 

 seem to be much smaller than the larger ones of Santo Domingo 

 and Gatun. Santo Domingo examples measure: 



Length 71, diam. 55 mm., 4^ post-embryonic whorls. 



Length 27.5, diam. 20.5 mm.,2f post-embryonic whorls. 



In specimens of all sizes, the furrows are nearly or quite as wide 

 as the spiral ridges, thus differing from the two forms following. 

 62 examples in the Gabb collection. 



Malea elliptica Pil«. and Johns. Plate, XXIX, flg. 3. 



Proc. A. N. S. Phila., 1917, p. 169. 

 Malea goliath Pils. and Johns. PL 29, figs. 1, 9. 



Proc. A. N. S. Phila., 1917, p. 170. 



