TRANSACTIONS OF WAGNER 



TERTIARY FAUNA OF FLORIDA 



This is a small and typical species, very abundant at the last-mentioned 

 locality, but more or less distorted or defective, owing to the delicacy of the 

 shell. 



Other species described under this name belong elsewhere. P. Mauryi 

 Harris is a Phenacomya (see p. 823) ; P. abrupta belongs in Margaritaria; 

 the Californian species appear to belong to the Cretaceous. There are two 

 species described from the recent American fauna, P. Candida Sowerby, the 

 type of the genus, from the West Indian Island of Tortola, and P. arata Ver- 

 rill, which in my opinion does not belong in this genus and may form a new 

 one, as follows : 



Genus APOREMA Dall. 



Type Pholadomya arata Verrill, Am. Journ. Sci., xxii., p. 301, Oct., 1881 ; Trans. Conn. 

 Acad., v., p. 567, pi. Iviii., fig. 37 ; vi., p. 278, pi. xxx., figs. 4-6, 1884. 



Off Martha's Vineyard, Massachusetts, in seventy-one to one hundred and 

 thirty-four fathoms. 



Shell trigonal, cuneate, nacreous, with radiating sculpture, a large lunular 

 and narrow dorsal area, the surface granular under a delicate periostracum ; 

 hinge consisting of an external strong ligament seated on strong nymphs, the 

 hinge-plate edentulous, interrupted under the beaks by an indentation; pallial 

 line not sinuated. 



The lamina on the type specimen referred to by Professor Verrill has the 

 appearance of being pathological, and in the hinge of the left valve of another 

 specimen there is no corresponding socket. The pallial line is obscure, but 

 seems to be certainly not sinuated. There is no indication of any lithodesma. 



This group will include Pholadomya africana Fischer and P. Locardi Dall 

 (P. arata Locard, Talisman, Rep. ii., 165, pi. viii., figs. 1-5, 1898, not of Ver- 

 rill, 1881) from deep water off the coast of west Africa, and perhaps the P. 

 Loveni Jeffreys, which, however, has the hinge-plate not interrupted and sculp- 

 ture more like the true Pholadomya. It is separated from Pholadomya by the 

 hinge-characters, form, and absence of a pallial sinus, from the Lyonsias by 

 the wholly external ligament, absence of a lithodesma and of a pallial sinus. 



Genus MARGARITARIA Conrad. 

 Margaritaria abrupta Conrad. 



Pholadomya abrupta Conrad, Fossil Shells of the Tertiary Form, of N. Am., p. 26, pi. 

 xii., figs. I, 2, 1832 ; Foss. Medial Tert., p. 3, pi. i., fig. 4, 1838 ; Proc. Acad. Nat. Sci. 



