140 BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



and look like unidentifiable fragments. This species is the only one 

 so far known in our faunal area with approximately equal sized open- 

 ings and can not very well be grouped with any other species. 



The following two species, Cadulus acus and C. dominguensis, possi-. 

 bly identical, may be separated from all other known Caduli of our 

 faunal areas by reason of their extreme slenderness and by the position 

 of the equator immediately behind the anterior aperture so that the 

 shells superficially appear to belong to the DentaHa rather than to the 

 Caduli. This is the Group 4 referred to in the comments on the sub- 

 genus Gadila. 



CADULUS (GADILA) ACUS Dall. 



Plate 20, fig. 11, 13. 



1889. Cadulus acus Dall, Bull. Mus. Comp. Zool., vol 18, p. 432, pi. 27, fig. 11. 



1889. Cadulus acus Dall, Bull. 37, U. S. Nat. Mus., p. 78, pi. 27, fig. 11. 



1898. Cadulus (Gadila) acus, Pilsbry and Sharp, Tryon's Man. Conch., vol. 17, 



p. 191, pi. 36, fig. 27. 

 1901. Cadulus acus Dall and Simpson, Bull. U. S. Fish Comm. for 1900, p. 457. 

 1903. Cadulus acus Dall, Bull. 37, U. S. Nat. Mus., p. 78, pi. 36, fig. 27. 



The shell is small, exceedingly slender, slightly curved, very gradu- 

 ally and evenly increasmg in diameter from a very small apical ori- 

 fice to the equator, situated immediately back of the anterior aperture, 

 from which point the cylinder rather abruptly contracts in the short 

 distance thence to the larger aperture. There is no local swelling and 

 the shell is not flattened. Many growth lines upon the posterior one- 

 third of the shell are emphasized into almost a sculptural feature of 

 densely packed circular riblets. The surface in all the specimens of 

 the type lot is remarkably variegated by bands of greater opacity of 

 varying widths. The apical features are simple. Measurements are: 



Length, 8 mm,; diameter, 0.75 mm.; anterior aperture, 5 mm.; 

 apical aperture, 0.12 mm. (Dall). 



The type. Cat. No. 95379, U.S.N.M., was collected by Couthouy in 

 30 fathoms, and is from a lot of many specimens. 



In the National Museum collection are also a lot of specimens. Cat. 

 No. 161583, U.S.N.M., from the U. S. B, F. Station 6062, .in Mayaguez 

 Harbor, Porto Rico, 25 fathoms, bottom of sand and mud, tempera- 

 ture 75.8° F.; one specimen, "Santo Domingo," Cat. No. 314820, 

 U.S.N.M., from Sowerby and Fulton; lot of three specimens. Cat. 

 No. 108173, U.S.N.M., from U. S. B. F, Station 2668, off Fernandina, 

 Florida, in 294 fathoms, bottom of gray sand, temperature 46.3° F. 

 The deeper and colder water station of' this last lot raises a doubt as 

 to the proper identification of these shells. However, the likelihood 

 of the dead specimen being swept off the Bahaman platform near-by 

 may be considered. 



Other lots in the Philadelphia Academy of Natural Sciences collec- 

 tion are from Charlotte Amalia Harbor, St. Thomas, 5 fathoms; 



