64 BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



DENTALIUM (FISSIDENTALroM) FLORIDENSE, new species. 



Plate 10, figs. 1, 2, 6, 7. 



1885. Dentalmm capillosum, Watson, Challenger Report Scaphopoda, p. 1, in 



part. (Not of Jeffreys.) 

 1889. Dentalium capillosum, Dall, Bull. Mus. Comp. Zool., vol. 18, p. 425, in 



part. (Not of Jeffreys.) 

 1889. Dentalium capillosum, Dall, Bull. 37, U. S. Nat. Mus., p. 76. (Not of 



Jeffreys.) 

 1897. Dentalium capillosum, Pilsbry and Sharp, Tryon's Man. Conch., 17, p. 



77, in part and omitting figures on pi. 8. (Not of Jeffreys.) 

 190.3. Dentalium capillosum, Dall, Bull. 37, U. S. Nat. Mus., p. 76. (Not of 



Jeffreys.) 



The shell is solid, regularly but not greatly curved and rapidly in- 

 creasing in diameter. Early part of tip awl-shaped and very slender. 

 The section almost round. Yellowish white in color, porcellanous, 

 but not shining. The tip is hexagonal, the angles pinched up into 

 sharp ridges, separated by smooth slightly concave spaces between. 

 At about 12 mm. from the apex intercalation of one rib in each inter- 

 costal space takes place, the six original angles broaden into primary 

 ribs, and the section of the shell becomes round. The ribs increase 

 to 24, become rounded, and of approximately equal importance and 

 are separated by spaces of equal width; all the ribs persist to the 

 oral aperture. The entire surface is covered by wavy growth lines 

 which though more prominent on the posterior portion are always 

 observable. These impart a roughened appearance to the longi- 

 tudinal ribs which is better seen under a lens. There is a long, 

 narrow apical slit on the convex side. 



Length, 62 mm.; greater diameter, 8.5 mm.; lesser diameter, 8 

 mm.; arc, 3. Type. 



Length, 74 mm.; greater diameter, 10 mm.; lesser diameter, 9.75 

 mm.; arc, 3. 



The type, Cat. No. 314457 U.S.N.M., was dredged by the Eolis 

 at her Station 301 off Sand Key, Florida, in 95 fathoms, rocky 

 bottom. 



Lots from various stations off Key West and Fowey Light, Florida, 

 35 to 110 fathoms, collected by the Eolis, and from Barbados in 100 

 fathoms, taken by the Hassler mark the only museum collection 

 records. 



The recent addition to the museum collection of excellent speci- 

 mens from the edge of the Gulf Stream off the Florida Keys showing 

 perfectly preserved tips as weU as living adidts, makes possible the 

 definite diagnosis of this somewhat misunderstood species. 



A comparison of our shell with Jeffrey's series of Dentalium capil- 

 losum from North Atlantic stations removes any question of their 

 specific identity. I have not seen Watson's subspecific D. c. pauci- 

 costatum, but the description of this eastern Atlantic mollusk shows 



