24 TRANSACTIONS OF THE WAGNER FREE 



SuPERORDER STREPTONEURA. 

 Order CTENOBRANCHIATA. 



Superfamily TOXOGLOSSA. 



Family TEREBRIDtE. 

 Genus TEREBRA Brugui^:re. 



Section ^cus (Humphrey) Gray. 



Terebra (Acus) dislocata Say. 

 Cerithiuin dislocatum Say, Journ. Acad. Nat. Sci. Phila., II. p. 235, 1822. 

 Terebra Peliiii Kiener, Mon. Ter., p. 37, plate xiii. figure 32, 1838. 

 Terebra rudis Gray, P. Z. S., 1834, p. 60. 



Terebra dislocata Holmes, Post-Pl. Fos. S. C, p. 70, plate xi. figure 12, 1858. 

 Terebra carolinensis (Conrad, ex parte^j Holmes, op. cit., p. 70. 

 Terebra dis/ocalum Emmons, Rep. N. Car. Gaol. Sur., p. 257, 1858. 



Habitat, Eocene of Mississippi (var. iantula Conr.) ; Miocene of Virginia, 

 North Carolina and of Ballast Point silex-beds, Florida; Pliocene of the Caro- 

 linas ; Caloosahatchie beds ; Post-Pliocene of the whole coast from Maryland 

 southward. Recent from Maryland southward to Florida, the Bahamas and 

 Venezuela. 



This well-known form indulges in many variations and lias a dwarf variety 

 which indulges in a parallel series of variations. Some of its examples agree 

 exactly with Eocene specimens of T. tantula Conrad ; and specimens which 

 have been identified by good authorities with T. diviszira Conrad, though not 

 the typical form of that species, are critically close to some of the recent shells. 

 The specimen from Ballast Point is about half way between T. tantula and 

 T. protexta. Miocene specimens from South Carolina are before me, agreeing 

 exactly with the large typical dislocata var. rudis. Among the recent shells 

 any one of the variations above noted can be duplicated. 



Terebra (Acus) concava Say. 

 Turritella concava Say, Journ. Acad. Nat. Sci. Phil., V. p. 207, 1827; De Kay, N. Y. Moll., 



p. 113, 1843. 

 Cerithiiim concavum Ravenel, Cat. 14, 1S34. 

 Acus concaviis Dall, Rep. Blake Gastr., II. p. 63, 1889. 



Caloosahatchie beds, not uncommon. 



This species varies greatly. It has a stout form and a slender form. Both 

 of these have varieties with weak and with strong sculpture. The typical 

 form oi concava has a strong nodulous rib on each side of the suture, with the 

 middle of the whorl constricted and sculptured with fine spiral lines. This 

 appears very distinct, but graduates toward the dwarf form of T. dislocata and 

 the finely sculptured form of T. protexta when a sufficient number of specimens 

 from a large range of coast are compared. The fossil specimens vary in ex- 

 actly the same way that the recent ones do. 



