NO. 30 SMITHSONIAN EXPLORATIONS, IQI2 59 
conditions in the narrow space between the main shore and the outer 
beach of the off-lying keys, each of which is occupied by a peculiar 
faunal assemblage. 
On April 28, 1912, the party crossed the Gulf Stream and pro- 
ceeded to Nassau, New Providence, where collections were made 
of living mollusks, and a fine series of the fossil mollusk, Cerion agas- 
sisi Dall, was obtained. 
The party then went to Andros Island. Here the marine mollusks 
proved rather disappointing, there being but few species and these, 
CPi FRM B : 
-_ 
Fic. 65.—The laboratory, “ White House,” near Sharp Rock Point, 
Andros Island. Photograph by Bartsch. 
as a rule, were few in number. The land shells were far more 
interesting, the genus Cerion in particular offering some most inter- 
esting problems. 
Andros Island is a collective term applied to a whole host of minor 
keys that are separated by tortuous channels of varying width and 
depth. Practically every key examined, no matter how small, pro- 
vided it bore vegetation, was found to be inhabited by Cerions of the 
C. glans group. The shells on each key present differences sufficient 
to enable one to distinguish them. For example, in size alone, 500 
of those collected about Bastion Point filled a 3-pint measure, while 
the same number from the neighborhood of our temporary laboratory, 
