299 
1908, I found that his description and figures of Tapes senescens 
Doederl. from Northern Italy agreed with that of 7'. eemiensis. Having 
now (1912) in Rome examined the specimens of the true T'. senes- - 
cens from the vicinity of Monte Mario near Rome and from other 
places in Italy (see p. 291—94), I must maintain that the 
Tapes senescens and T. aureus var. eemiensis are identical. 
Tapes senescens Doederl. is for the first time described and 
figured by Cocconi from some specimens in the Museum of Parma, 
denominated by Prof. Doederlein, and his diagnosis is reprinted 
on p. 289. He, as well as Cerulli-Irelli, lays stress on just 
the same characters as I have done for 7'. eemiensis: the tumid 
scape, more or less produced or caudate in the posterior end, the 
prominent and recurved beaks and above all the characteristic 
irregular (rugosa) sculpture on the posterior part of the valve. — 
The relationship between Tapes senescens and T'. aureus s. str. is 
not cleared up in a satisfactory manner. The best distinction 
marks are the size and the sculpture, but they are both very 
variable and the rugose sculpture can be greatly diminished and 
nearly obliterated. 
The age of the North-Italian deposits, in which Tapes senes- 
cens is found, is not definitely established. In the neighbourhood 
of Rome it is found in some lagoon deposits (sand or clay), younger 
than the classic, fossiliferous marine beds of Monte Mario, but 
older than the strata of volcanic tuff. The classic beds are con- 
sidered as belonging to the Upper Pliocene or "Lower Pleistocene” 
(De Stefani) or forming a passage from Plio- to Pleistocene (Ce- 
rulli-Irelli), and the volcanic tuff is of pleistocene age. With 
regard to the details in the succession of the deposits at Monte 
Mario, see the litterature quoted on p. 295, Note 1. 
