36 MOLIvUSCA OF THE GULF OF MEXICO 



Distribution — Hatteras to Cuba, 22-182 fms. Type dredged 

 between Mississippi delta and Cedar Ke3"s in 30 fms. 



(Atualis) bartletii Henderson, Bull, iii, U. S. N. M., p. 55, pi. 

 8, f. 2,7, 1920. 



antillariiin Ball, Bull. M. C. Z. , 9, p. 37, 1881 ; Bull. 37, 

 U. S. N. M.. p 76 {pars), i88g. Not antillar^ivi d'Or- 

 bigny, 1846. 



Note. — True antillariun is semi-littoral while bartletti xs \\\ 

 deeper, colder waters. 



Distribution. — Florida to Martinique. Gulf of Mexico: Be- 

 tween Mississippi delta and Cedar Ke^'s, 227 fms.; Yucatan 

 Banks, 399 fms. 



(Heteroschisma) ealiithrix Dall, Bull. M. C. Z., 18, p. 427, pi. 27, 

 f. 10, 1889; Bull. 37, U. S. N. M.,p. 76, pi. 27, f. 10, 1889; 

 Pilsbry & Sharp, Tr5'on's Man. Conch 17, p. 62, pi. 7, f. 3, 

 1S97; Henderson. Bull, in, U. S. N. M., p. 57, pi. 8, f. 3, 

 4, 6, 1920. 



Distribution — North Carolina to off Rio de la Plata, Ar- 

 gentina. Gulf of Mexico: Between Mi.ssis.sippi delta and 

 Cedar Keys, 1 181 fms.; Yucatan Strait, 640 fms. (type lo- 

 cality). 



(Fissidentallum) meridionale Pilsbry and Sharp, Tryon's Man. 

 Conch., 17, p. 73, pi. 15, f. 32-34, 1897, (as variety of <ra?z- 

 didum); Henderson, Bull, in, U. S. N. M., p. 61, pi. 9, f. 

 2, 1920. 



rmri- Dall, Bull. M. C Z. 9, p. 37, i88i;i8, p. 425, 1889; 

 Proc. U. S. N. M. 12, p. 294, 1889. Not ceras Watson. 



Distribution — Type dredged by the Albatross, 240 miles south- 

 east of Rio de Janeiro, 671 fms., 37° temperature bottom. 

 Also found Yucatan Banks, 1568 fms. and off Barbados. 

 The largest Dentalium of the western Atlantic and charac- 

 terized by its unique, ashen color. 



