EAST AMERICAN SCAPHOPOD MOLLUSKS. 69 



increases the original number and all finally decrease in definiteness 

 and merge into a rounded surface. Growth lines, "scratch-like 

 puckerings," are present, about 55 to each one-tenth inch. The 

 apical feature consists of an irregular ragged fissure on the convex 

 side. 



Length, 1.93 inches; diameter 0.13 inch (49.02 mm. by 3.3 mm.). 



The type is in the British Museum collection. This species is 

 quoted by Watson as occurring on both sides of the Atlantic, the 

 western Atlantic records being off Sombrero Island in 470 fathoms, 

 Challenger Station 23; off Bermuda in 1,075 fathoms. Challenger 

 Station 56, and off Pernambuco in 350 fathoms, Challenger Station 122. 



There are no examples in the National Museum collection, nor have 

 I seen specimens. The description suggests a shell belonging to the 

 group of DentaliuTn hartletti. 



DENTALIUM (GRAPTACME) SEMISTRIOLATUM Guilding. 



Plate 11, figs. 1, 2, 3, 8, 9. 

 (?) 1819. Dentalium semistriatum Turton, Conch. Diet. British Isles, p. 39, 



pi. 18, fig. 68. 

 (?) 1825. Dentalium nebulosum Deshayes, Mem. Soc. Hist. Nat., Paris, vol.2, 

 p. 369, pi. 16, fig. 20 (Not of Gmelin). 

 1834. Dentalium semistriolatum Guilding, Trans. Linn. Soc, London, vol. 17, 

 pt. 1, p. 34, pi. 3, figs. 1-5. 

 (?) 1843. Dentalium translucidum' Ghenu, Conch. 111., vol. 1, p. 8, pi. 3, fig. 12 



(Not of Deshayes). 

 (?) 1843. Dentalium nebulosum, Chenu, Conch. 111., p. 5, pi. 6, fig. 4. 



1843. Dentalium semistriolatum, Chenu, Conch. HI., p. 7, pi. 4, figs. 14, 15. 

 1843. Dentalium semistriatum, Forbes and Hanley, Hist. Brit. Moll., vol. 

 2, p. 454. 

 (?) 1860. Dentalium nebulosum, Sowerby, Theasurus, vol. 3, p. 98, pi. 225, fig.58. 

 (?) 1873. Dentalium nebulosum, Sowerby, Reeve Conch. Icon., vol. 18, pi. 7, 



fig. 53. 

 (?) 1896. Dentalium nebulosum, Clessin, Syst. Conch. Cab., vol. 6, pt. 5, p. 19, 



pi. 5, fig. 5. 

 (?) 1897. Dentalium (Graptacme) semistriatum, Pilsbry and Sharp, Tryon's 

 Man. Conch., vol. 17, p. 90, pi. 16, fig. 51, 52, 53. 

 In selecting Guilding's name from a somewhat confused synonymy 

 I have taken the first that is expressly c^uoted from the Antilles, and 

 which is also accompanied by a figure and description which leave 

 no reasonable grounds for doubt. Deshayes's and Chenu's Denta- 

 lium nehulosuin, especially as interpreted by Sowerby in the Thesaurus 

 and in Reeve, seems likely to be this species, despite the vagueness of 

 the localities given, some of which, however, are Antillean. Tur- 

 ton's D. semistriatum, as pointed out by Forbes and HaiUey, is 

 merely " exotic" and it may be this species. Chenu's D. translucidum 

 (not of Deshayes nor of Sowerby in Reeve) is very suggestive, but 

 is left without definite locality and may or may not be our species. 

 I have excluded references to Pacific forms, generally regarded as 

 synonymous, as I believe them to be distinct from our species. 



