FREE INSTITUTE OF SCIENCE 

 TERTIARY FAUNA OF FLORIDA 



Pliocene of Costa Rica, Gabb, and of the Caloosahatchie marl at Shell 

 Creek, Willcox; Pleistocene of Florida, South Carolina (Simmons Bluff), and 

 of the Antilles; living from Cape Hatteras, North Carolina, to Guadelupe 

 Island, West Indies. 



The figures given of iiniscosiis disclose no differences in the minor sculp- 

 ture or the number of ribs, and there are no discrepancies in the description, 

 compared with that of exasfcratiis. The locality originally given for the latter 

 has not been confirmed, and that given for inuscosiis may prove erroneous. 

 In this case, the latter name would take precedence. I have little doubt of 

 their identity, but do not unite them because I have seen no authentic speci- 

 mens of nniscosus. 



The present species is moderately tumid, and has a scabrous sculpture 

 besides traces of the Camptonectes striation. The backs of the ribs are set, in 

 perfect specimens, with small, sometimes clavate spines, and there are from 

 one to four fine threads on each side of the main keel which are usually more 

 or less prickly. The middle of the interspaces is, however, usually free from 

 the radial sculpture. Adult specimens with the spines considerably worn are 

 such as Conrad called fuscopurpureus. The colors of the shell are very 

 varied, including brown, white, yellow, pink, and various shades of red, either 

 simply unicolored or mottled. In the mottled brown ones it is common to 

 see from three to five of the ribs uniformly white from end to end, or of a 

 lighter color than the rest ; this forms the triradiatus type. I have examined 

 sixty-nine adult valves, of which ten had seventeen ribs, thirty-three had 

 eighteen ribs, twenty-three had nineteen ribs, and three had twenty ribs; the 

 normal number, therefore, being eighteen to nineteen. The young shells are 

 more rotund than the adults, and their ears are proportionately more con- 

 spicuous. Guppy (Geol. Journ., xxii., p. 294) cites this species as occurring 

 in the Oligocene of Jamaica, but the specimens he refers to present certain 

 differences and are probably distinct. 



Pecten (Chlamys) ornatus Lamarck. 

 I'-t ti-it urnatus Lain., An. s. Vert., vi., p. 176, 1819; Reeve, Conch. Iconica, xix., fig. 



(>K, 1853. 

 .' <)x/>;;i .wrfi-f<i/ti Gmelin, Syst. Nat., vi., p. 3328, 1792; Chemn., Conch. Cab., vii., 



p. 345, pi. 69, fig. H. 

 :' ('/i/ii/i/vs Itfiitilicti Yuri-ill and lUish, Trans. Conn. Acacl., x., p. 74, 1897. 



Pleistocene of the Florida Keys and the raised reefs of the Antilles ; 



