INSTITUTE OF SCIENCE, PHILADELPHIA. 225 



sloping obliquely from the posterior carina to the suture, so that the latter is 

 really anterior to the carina ; umbilicus large and funicular ; aperture entire, 

 subtriangular; pillar with three sub-equal, equi-distant plaits, outer lip thick- 

 ened with about ten lirse, which stop short of the margin. There are a few 

 obscure lirations elsewhere in the aperture. Lon. of shell i6; of aperture 

 8.5 ; max. lat. of shell 11.6 mm. 



This elegant little species, by its peculiar spiral, even striation, like 

 wound silk, differs from all the other American species, recent or fossil, which 

 have come under my notice. There is no approach to reticulation except in 

 the earlier whorls, and very little there. 



Family OLIVID/E (supplementary). 



Genus ANOILLA Lamarck. 



Ancilla Lam., Prodr. Noiiv. Class., p. 70, 1799. 



Ancillaria Lam., Ann. dii Mus. xvi. p. 302, 1810. Dall, part i. p. 46. 



In conformity with the rules of nomenclature, the earlier form of the 

 name must be adopted. 



Family MARGINELLID^ (supplementary). 



Genus MARGINELLA Lamarck. 



Marginella eulima n. s. 



Plate 13, figure 10. 



Marginella limahila Dall, part i. p. 50 (spotted variety). 



Pliocene of Shell Creek (Willcox) and the Caloosahatchie beds. 



Shell differing from M. liniahtla Conrad in being uniformly narrower and 

 more cylindrical, with a spotted surface, less angulated at the shoulder, with 

 a wider canal, a more denticulated outer lip and a nearer approach to the tip 

 of the spire by the posterior commissure of the aperture. Lon. of shell 13.O; 

 max. lat. 6.6 mm. 



The reception of more perfect and more numerous specimens of this 

 form from Mr. Willcox enables me to definitely separate it from the typical 

 limatula. An examination of a large number of the recent limahila fails to 

 show any spotted specimens. The spotting on M. eidivia is of opaque white 

 flakes on a translucent enamel which has sometimes turned yellowish. The 

 only recent species which approach M. eidinia are M. priiinosa Hinds, from 

 which the former differs by its greater posterior attenuation, its less marked 

 shoulder-angle, more flexuous outer lip, and in the presence of the thick and 

 widespread callus on the body ; and M. nivosa Hinds, which is more the 

 shape of the present species, but larger, stouter, and having numerous small 

 differences of detail. It is not unlikely, however, that M. eulima is the Plio- 

 cene ancestral form of M. nivosa. 



