TRANSACTIONS OF WAGNER 



744 



' ^ TERTIARY FAUNA OF FLORIDA 



living throughout the West Indies at depths of one hundred fathoms or less, 

 and extending from Bahia, Brazil, to the shores of the Gulf of Mexico, and 

 north to the vicinity of Cape Lookout, North Carolina, in from fifteen to fifty- 

 two fathoms. Also {P. Bciicdicti), dead, off shore in lat. 40° 9' N., Ion. 67° 

 9' W., in thirteen hundred and fifty-six fathoms (?). Also in the Red Sea (?). 

 This elegant species (to which P. inultisqnamatus Dunker, of Cuba, seems 

 closely allied) is extremely variable in color and surface sculpture, and has 

 some relations to P. meinbranosiis. The shell which has received the name of 

 Benedicti is only six millimetres in height and possesses no adult characters. 

 Similar shells are, however, rather common in places in the Gulf of Mexico 

 and West Indies, where P. ornatus abounds, and, after comparison with the 

 umbones of half-grown ornatus, I am disposed to think the two should be 

 united. 



Pecten (Ohlamys) indecisus n. s. 

 Plate 34, Figure 3. 



Vicksburgian Oligocene at Archer and vicinity, Alachua County ; as 

 silicious pseudomorphs at Martin Station, Marion County; at a depth of two 

 hundred and twenty-five feet in the artesian well, Ponce de Leon Hotel, St. 

 Augustine ; and in the Tampa limestone of the Hillsborough River, near 

 Tampa, Florida ; Dall and Willcox. 



Shell thin, moderately convex, ovate, with twenty-six to thirty-four small, 

 low, simple, entire ribs separated by about equal interspaces and having a ten- 

 dency, especially in the left valve (which is slightly more convex than the 

 other), to become obsolete distally; transverse sculpture only of lines of 

 growth, Camptonectes striation present, more conspicuous in the smoother 

 specimens ; ears small, unequal, the posterior smaller ; byssal ear with a well- 

 marked notch and conspicuous fasciole, above which are about six partly 

 scabrous riblets, becoming stronger dorsally; interior lirate, the lirse stronger 

 near the margin ; ctenolium present ; cai'dinal crura well developed, cross- 

 striated. Alt. of figured specimen 16, of adult 31, lat. of adult 28 mm. 



This is a very interesting species which retains the outline of Chlamys 

 while at times it assumes the characters of Anmshnn. Some specimens are 

 almost ribless, except on the umbones, and in this state the species would 

 belong to the " subgenus" Lissopectcn Verrill ; in others the ribs are well 

 developed and continuous down to the very margin, which they then crenulate ; 

 in which state the shell is a typical Chlamys. In most of its shell characters 

 it is intermediate between the two subgenera, Chlamys and Amusium. Just 



