109 MOLLUSCA OF THE GULF OF MEXICO 77 



Tex. Pleistocene : New Orleans well of 1856, 41 feet, 

 Lake Borgne borings. Grand Chenier, Knapp's wells, Ter- 

 rebonne Parish, No. 2 at 1050-1190, 1542-1632, 1791- 

 1839, No. 3 at 570-700, 1400- 1 550 feet. Upper Miocene: 

 Galveston deep well at 2236-2600 feet (Harris). 

 Note. — It was from the violet margins of V. viercenaria that 

 the Indians of the East coast made the discs of purple 

 wampum which was more costly than the white. 

 campechiensis Gmelin, Sj^st. Nat. 5, p. 3287, 1792 ; Dall, Tr. W. 

 I. S., 3, p. 1 315, 1903 ; Vaughan, Publ. 134, Carn. Inst., 

 p. 171, 1910. 

 prcBparca Say, 1822 ; mortoni Conrad, 1837 ; Holmes, Post- 

 PL F. S. C, p. 34, pi. 6, f. 12, 1858; calcarea Philippi, 

 1844 ; te7iuilamellata Sowerby, 1853 ; alboradiata Sower- 

 by, 1853, Reeve, Conch. Icon., pi. 3, f. 7, 1863 ; tetrica 

 Conrad, 1838 ; permagna Conrad, 1838, Tuomey and 

 Holmes, Pleio. Fos. S. C, p. 86, pi. 22, f. 2, 1856 ; capax 

 Conrad, 1863 ; submorioni d'Orbigny, 1852 ; obtusa, '66, 

 ciineata, '68, and carolinensis, '75, Conrad. 

 Distribution. — Chesapeake Baj^ to Yucatan, moderate depths. 

 Miocene to Recent. Gulf coast. — Recent : Indian Pass, 

 Crooked Isl., Cedar Keys, Fla. ; Horn Isl., Miss. ; Cam- 

 eron, Chandeleurs, La. ; Corpus Christi, Alligator Head 

 (dredged), Pass Cabello, Matagorda Bay (immense shells, 

 Mitchell), Galveston, Texas. Dall has named the Texan 

 form var. texana. Pleistocene : Labelle and Osprey, 

 West Fla. PHocene : Shell Creek, Fla. 



Genus GEMMA Deshayes 

 gemma Totten, var. purpurea H. C. Lea, Am. Jour. Sci., p. 106, 

 pi. I, f. I, 1842, (as Cyrena); Dall, Tr. W. I. S., 3, pi. 24, 

 f. 2, 4, 4 b, 1898 ; p. 1332, 1903 ; Vanatta, Proc. A. N. S. 

 Phila., 55, p. 757, '03 ; Johnson, Occ. Papers, Bost, Soc. 

 N. H., 7, p. 71, 1915. 

 Parastarte concentrica Dall. Bull. 37, U. S. N. M., p. 48, 



1889, Nomen nudtivi. 

 f manhattanensis Prime, Jay's Cat., 4th ed., Suppl., p. 466, 



