TRANSACTIONS OF WAGNER 

 714 



TERTIARY FAUNA OF FLORIDA 



centric linear imbrication ; form tumid, cardinal crura well marked ; left valve 

 less convex than the other. Alt. and lat. about 15 mm. 



The above diagnosis is from the type of P. angusticostatus, and agrees 

 with Sowerby's diagnosis. The shells which are now found under the name 

 of Sowerby in the Heniker collection are, according to Mr. Reid, a pair (A) 

 which are orbicular, suboblique, not tumid, with a well-marked small rib in 

 each furrow, coarsely squamose sculpture, and a height of forty-seven and a 

 half millimetres. The other specimen (B) is a single valve with the rib in the 

 furrow obsolete or absent, the shell oblique, surface coarsely squamose. The 

 two are not certainly the same species, and both of them conflict in character 

 with Sowerby's diagnosis. I cannot accept them, therefore, without further 

 evidence, as being the originals. Specimen A recalls strongly the shell here 

 named P. Gabbi, and may be a specimen of that species which has been acci- 

 dentally labelled with a name not belonging to it. In case this view is not 

 accepted, in spite of the discrepancies between the specimen and Sowerby's 

 description, the present form will take Gabb's name. 



Pecten (^quipecten) ingequalis Sowerby. 

 Pecieji inaqKalis Sby., op. cit., p. 52, 1849; Guppy, Geol. Journ., xxii., p. 294, pi. 18, 

 fig. 6, 1866. 



Oligocene of St. Domingo and Haiti, Gabb ; Jamaica, Bland; Cura9ao, 

 United States Fish Commission ; Isthmus of Darien, Hill. 



This much resembles P. angusticostatus Gabb in form, and size, but the 

 ribs are rounded and the interspaces roundly concave. It is the most common 

 and widely distributed of the Antillean Oligocene Pectens. 



Peoten (.ffiquipecten) thetidis Sowerby. 

 Pcctcn tJietidis Sby., op. cit., p. 52, 1849. 



Oligocene of St. Domingo, Heniker; Bowden, Jamaica, Henderson and 

 Simpson ; Curasao, United States Fish Commission. 



This is a shell much resembling the recent Florida shell which Conrad 

 named fiiscopiirpurcus, but the latter is larger and less solid. The specimens 

 in the Heniker collection include two indeterminable valves : (A) four tumid, 

 inequilateral, equivalve, with nineteen sharp ribs and sharp furrows, sculpture 

 squamose ; (B) one orbicular compressed valve with nineteen ribs which are 

 markedly quadrate at the margin, squamose and wrinkled, but scarcely spiny, 

 the ribs of the disk and those of the wing forming a nearly continuous series. 



