INSTITUTE OF SCIENCE, PHILADELPHIA. 1 39 



Of this subgenus, Guppy (1874) describes a species from the Pliocene of 

 Trinidad, under the name of Cohimbella pecidiaris, but I cannot make his 

 description agree with the present form. 



Before leaving this family I may add that Strovibina exilis of Gabb, from 

 the Miocene of Santo Domingo, is an Anacliis, and Guppy thinks it may be 

 synonymous with the prior and unfigured ColuvibcHa liaitcnsis Sowerby. 



Family MURICID^. 



Genus MUREX Linn^. 



Subgenus Murex s. s. 



Murex messorius Sowerby. 



M. messorius Reeve, Conch. Icon. Murex, fig. 90, 1S45 ; Dall, Blake Gastr., p. 196, 1S89 ; 



not of Tryon. 

 M. recurvirostris Gabb, Geol. Rep. St. Domingo, p. 201, 1873, not of Broderip. 



Fossil in the Pliocene marls of the Caloosahatchie River and Alligator 

 Creek, Florida, and also of Costa Rica. Post-Pliocene of Santo Domingo ; 

 living in the Antilles and on the western coast of Florida and the Keys. 



The specimens collected, though small, agree perfectly with recent 

 specimens. 



Murex chrysostoma Gray, var. chipolana Dall. 



Lower Miocene of the Chipola River, West Florida, near Bailey's Ferry ; 

 Ballast Ft. silex-beds (?). 



The specimens from the Chipola River differ from the recent M. chrysos- 

 torna in being smaller than the average adult recent specimens, with a slightly 

 shorter canal, from which the antecedent canal tends to divaricate, while in 

 the typical chrysostoma it is usually continuous. 



The anterior margin of the varices in the fossil also tends to be more spi- 

 nose or to have the projecting points more produced than in the recent shell, 

 though similarly situated and similar in number. 



Murex mississippiensis Conrad. 

 M. mississippiensis Conrad, Journ. Acad. Nat. Sci. Phila., 2d series, vol. i, p. n6, pi. xi. 



fig. 30, 1848. 

 M. tritonopsis Heilprin, Trans. Wagner Inst. i. p. 107, pi. 15, fig. 39, 1887. 



Fossil in the Upper Eocene or Vicksburg beds of Mississippi ; the Lower 

 Miocene of the Chipola River, West Florida, and of the silex-beds at Ballast 

 Point, Tampa Bay, Florida. 



The characters relied upon for the separation of M. tritonopsis are not con- 

 firmed by better preserved and more plentiful material. The nodes or trans- 

 verse plications between the varices and the spiral sculpture, when perfectly 

 preserved, are identical in the Eocene and Miocene specimens. It is observa- 

 ble that in many of the siliceous pseudomorphs the spiral or other fine sculpt- 

 ure is not reproduced in the silex as sharply and completely as it existed in 



