OQ, Meyer—Species im the Southern Old-tertiary. 465 
With fine, closely set, elevated revolving lines. In the largest of 
my Vicksburg specimens the following can be seen: In the 
youngest reticulated whorl there are only the large revolving lines, 
then a small line appears in the middle of the large ones and final- 
ly one more line appears in the interstices. If we imagine this 
process repeated twice more, we obtain the finely striated surface 
of F. filius, and indeed this same process can be traced along the 
whorls of the Jackson form, so that we can say, the young /% 
Jilius repeats the old F. Mississippiensis. 
7 Marginella in Jackson agrees essentially with specimens 
from Claiborne, which I determined as Marg. incurva Lea, bu 
seems to be generally larger and much inclined to deposit callus 
on the posterior part of the mouth. It may be called var. Juck- 
sonensis, 
74. Mitra dumosa C., from Jackson, is more slender and orna- 
mented than MW. paetilis C., from Claiborne, but both qualities 
vary in both places and M. dumosa cannot be considered more 
than a variety. 
One of the most difficult genera is Oliva. On one side the 
‘Species vary very much, especially in form. Any doubt about 
this is removed by two specimens of a common species in Jackson, 
different species in the fossil state are distinguished only by small 
differences, 
I relate three species to each other, ove from Claiborne, deter- 
mined as Oliva gracilis Lea, the above mentioned one from Jack- 
8on, which is generally stouter, and Oliva Mississippiensis C., from 
Vicksburg, which is larger and again stouter and where the main 
Inflation is generally somewhat higher. The Jackson species may 
be called Oliva media. 
76. 
cellaria funerata, resembles muc n ; 
the common Cancellaria), A disagreement in the third embry- 
