EAST AMERICAN SCAPHOPOD MOLLUSKS. 33 



Seven specimens, Cat. No. 95330 (a), U.S.N.M., were taken by the 

 Hassler, U. S. C. S. Station 220, oif Sandy Bay, Barbados, in 100 

 fathoms. Specimens were also taken by the State University of 

 Iowa Expedition of 1918 in 125 fathoms, off Bridgetown, Barbados, 

 being State University of Iowa Station 62. 



The greater number of ribs removes this species from the D. texa- 

 fiianum grou]) ; the curiously roughened appearance suggests a fancy 

 that the shell had suffered a slight melting or softening of its surface. 

 The features appear to be very constant ; a narrow variation decreas- 

 ing the slight curve in the tip to an almost straight shell is observed 

 in a few specimens. 



It is evidently a moderate depth species of the lesser Antilles, 

 though as yet only recorded from Barbados. 



DENTALIUM (DENTALIUM) CARDUUS Dall. 



Plate 3, figs. 4, 5, 7. 



1889. Dentalium caiduus Dall, Bull. Mus. Comp. Zool., vol. 18, pt. 2, p. 423, 



pi. 27, fig. 3. 

 1889. Dentalium carduus Dall, Bull. 37, U. S. Nat. Mus., p. 7(5, pi. 27, fig. 3. 

 1897. Dentalium [Dentalium.) carduus, Pilsbry and Sharp, Tryon's Man. Conch., 



vol. 17, p. 30, pi. 7, fig. 6. 

 1903. Dentalium carduus Dall, Bull. 37, U. S. Nat. Mus., p. 7(i, pi. 27, fig. 3. 



The shell is very long and slightly curved, mostly in the posterior 

 third, increasing evenly in diameter; solid, but not thick; slightly 

 compressed dorso-ventrally. It is pure white, with an ashy hue, and 

 sometimes exhibits rusty patciies, possil)ly due to extraneous matter, 

 and is not polished or bright. The sculpture consists of 16 narrow 

 longitudinal ribs, which, just below the tip, are separated by wide, 

 flat spaces. These primary ribs are increased f)y intercalation, all 

 being of equal importance and continuous; though growing flatter 

 and wider, they do not disappear at the aperture, even in full}^ adult 

 shells. The entire surface is covered by elevated, transverse riblets 

 of whicli tliere are 16 to 20 to the millimeter, appearing like circular 

 lamellae, and which, in crossing the longitudinal ribs, produce a rasp- 

 hke surface. This feature is best observed in the posterior half of 

 the shell, but persists in modified degree even to the aperture. There 

 is a dorsally ])laced, rather deep apical notch. 



Length, 87 mm.; diameter, 7 mm. (Dall). 



Length, 77 mm.; diameter, 7 mm.; arc, 3.75 (Grenada). 



The type is in the Museum of Comparative Zoology, Cambridge, 

 Massachusetts, and was dredged off Santa Lucia, in 116 fathoms. 

 In the Ignited States National Museum are three lots: One specimen, 

 Cat. No. 95322, U.S.N.M., dredged at United States Bureau of Fisli- 

 eries Station 2655 on Little Bahama Bank, in 338 fathoms, sand 

 bottom, and temperature of 47.5°; one specimen, Cat. No. 95321, 

 U.S.N.M., taken by the Blalr at United States Coast Survey Station 



