70 



BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



These are Dentalium semipolitu7n Pilsbry and Sharp, D. liratuin 

 Carpenter, D. liratulum Morch, etc. Whatever the others with more 

 or less doubt may represent tliere can be no question that Gnilding's 

 D. semistriolatum does represent this very common shallow-water 

 Antillean species. The shell is rather strongly and regularly curved, 

 slender and regularly tapering, and has a round section. The color 

 is translucent white with milky patches; it is highly polished and 

 shining, with sometirnes a reddish tint about the apex. Zigzag 

 color bands of an opaque milky white encircle the shell, especially 

 upon its sculptured ]:)ortion, imparting a watered-silk appearance; 

 this feature, however, varies considerably in degree of prominence. 

 The sculpture consists of fine longitudinal, regularly spaced grooves 

 engraved upon the posterior third, fourth, or fifth portion of the 

 shell, the lines all abruptly ending at a given point, the balance of the 

 shell surface being glistening and smooth but for slight irregularities 

 of growth. There is a long, narrow apical slit on the side about 

 midway between a convex side and concave side position. Many 

 specimens do not show this character. 

 ' Dimensions vary within fairly broad limits; the extremes are: 



Length, 34 mm.; diameter, 4 mm.; arc 3 (St. Thomas). 



Length, 33 mm.; diameter, 2.5 mm.; arc, 2.5 (North Cuba). 



Length, 25 mm.; diameter, 3 mm.; arc, 2 (St. Martin). 



This is an abundant littoral species found, throughout the Carib- 

 bean region, more especially in the Lesser Antilles. Lots in the 

 National Museum collection are from Barbados, St. Martin, St. 

 Thomas, Dominica, Varadero (Cuba), Bimini, also from the Florida 

 Keys region, Tortugas to Miami, shore to 30 fathoms, and the west 

 coast of Florida in shallow water. It has not, however, been reported 

 from the Hatter as region. 



The following are the National Museum records: 



I/Ocality. 



Remarks. 



Bermuda 



North Bimini Island, EoUs Station 50 



Varadaro Beach, Cuba, Bar^era f^'tation 213. 



Samana Bay, St. Domingo (Dall) 



St. Martin 



St. Thomas (Pilsbry) 



West Indies (Sowerby and Fulton) 



Barbados 



do 



Off Miami, Florida, Eolis Station 49 



Off Miami, Florida, Eolis Station 62 



Off Miami, Florida, Eolis Station 312 



Off Fowev Light, Eolis Station 8 



Off Fowey Light, Eolis Station 121 



Sand Key, Florida, Eolis Station 98 



Tortugas, Florida, Eolis Station 34 



Tortugas, Florida, Eolis Station, 33 



West c^'oast, Florida 



Key West (North Florida), Eolis Station 20. 



West Coast 



Habana, Cuba 



(Goode.) 



20 fms. (fragments). 



(beach.) 



30 fms., s. CO. detr. 



20 fms. 



25 fms. 



25 fms. 



30 fms. 



70-90 fms. 



15 fms. 



(T.E. Benedict.) 



7 fms. 



10-12 fms. (T. E. Benedict). 



Sanchez. 



