1895. PROCEEDINGS OF THE NATIONAL MUSEUM. 33 



Genus TEREBRA, Bruguiere. 



This genus is one of the most difficult to handle from the inexhausti- 

 ble tendency to variation the species exhibit, and which reuders it 

 frequently almost impossible to come to any satisfactory conclusion as 

 to the relative rank and permanency of the mutations exhibited. Our 

 east American fossil species may be arranged in three series; Terebra 

 proper, with large, strong shells, the pillar with a single strong anterior 

 keel; Mastula, Adams, with the pillar smooth, the canal straight, and 

 the subsutural baud absent, feeble, or not set off by a sulcus; Actts 

 Adams, with the band and sulcus more or less distinct, a tendency to 

 reticulated sculpture, and the pillar with a flat callus at the aperture, 

 which usually bears farther back two more or less distinct plaits or 

 keels. The two latter may be regarded as subgenera. It is proper to 

 observe that nearly all the diagnoses of the groups in Terebridje contain 

 a proportion of error in matters of fact. . This is especially the case 

 wuth Hastula and jicus, Adams, whose arrangement is so generally 

 followed. 



In the Eocene we have T. {Ha,stu}a) rennsta, Lea, of which T.perlata, 

 Conrad, T. mitis, de Gregorio, and T. inula, de Gregorio, are synonyms 

 or mutations; T. /(OHs^o^m (Harris, MS.), new species; and T. {Aciis) 

 poJygyra, Conrad, of which T. andrefja and T. tgnara, de Gregorio, are 

 mutations. These species are all Claibornian, or older. In the later 

 Eocene of Vicksburg we have T. {Acus) dlvisura, Conrad, and its vari- 

 ety or mutation T. miruhi, de CJregorio, and T. (Acus) iauinhi, Conrad, 

 which extends up into the older Miocene of Haiti, the Orthaulax bed 

 at Tampa, Florida, and the Alum Bluff beds at De Funiak Springs. 



In the Miocene the genus is more numerously represented. Typical 

 Terehra appears in the Haitian old Miocene, which contains T. ijabhii, 

 Dall {rohusta, Gabb, not of Hinds), and T. haitensis, Dall, new species. 

 In the Chesapeake Miocene we have tiie T. unilineata, Conrad, a well- 

 marked species. 



Acus is represented in the old or Chipola Miocene by T. curvllineata, 

 new species, from Shiloh, New Jersey, and Easton, Maryland; T. bqxir- 

 tita, Sowerby (1849, not of Deshayes, 1859), T. sulcifera, Sowerby, T. 

 ina'qiiali.s, Sowerby, and T. houidoiii, Dall, new species, all of whicli are 

 common to Haiti and tlie Floridian Chipola beds; also T. pcr^nmctafa, 

 Dall, new species, and T. chijwhoia, Dall, new species, of the Chipola 

 beds. Later species of Acus are. T. dislocata, Say {indcnta, Conrad, ex 

 parte, indentata, Meek, by a typographical error, and ziga, de Gregorio), 

 which extends from the Chesapeake Miocene to the recent fauna; T. 

 caroUncnsis, Conrad, of the newer Miocene, at the Duplin Natnral Well, 

 North Carolina; T. cmmoiisi, Dall [neglccta, Emmons, 18.58, not of Mich- 

 elotti, 1847), of the Carolinas; T. concava, Say, ranging from the newer 

 Chesapeake Miocene to the recent fauna, and T. protexta, Conrad, from 

 the Pliocene to the recent fauna; T. curviUrata, Conrad, and T. poly- 

 Proc. N. M. 95 3 



