THE NAUTILUS. 3 
SOME REFERENCES TO THE GENUS OLIVA. 
BY JOHN FORD. 
Of all the marine univalves the Olives are perhaps among the 
most difficult to define specifically. It is true that the most irregu- 
lar forms can in some instances be readily determined and properly 
placed by expert concholoyists, for however greatly they may differ 
from the accepted types, certain characters, proving a common ori- 
gin, are always perceivable. This is especially the case with such 
species as O. inflata Lam., O. maura Lam., and O. perwviana Lam. 
(Fig. 1). 
To other species, however, many shells have been assigned which 
are apparently devoid of characters necessary to sustain the rela- 
tionship claimed for them. In this group may be included O. ara- 
neosa Lam., O. irisans Lam., O. ispidula Linn., and O. reticularis 
Lam. So variable both in form and color patterns are many of the 
shells assigned to these four species, it is not at all strange that they 
have been honored with scores of specific names. That a majority 
of these names are synonymous there is no reason to doubt, but it 
seems equally apparent that quite a number of the shells, the names 
of which have been thus subordinated, are really specifically dis- 
tinct from the types with which they are associated. 
Fig. 1. Fig. 2. Fig. 3. 
O. peruviana Lam. O. erythrostoma Lam. O. porphyria Lam. 
Among these may be noted O. ornata Marratt and O. julietta 
Duclos, which some recent writers have determined to be varieties 
only, the former of O. irisans, the latter of O. araneosa. If there 
