ACT.EON. 159 



of the last whorl, thin, simple, passing imperceptibly into the short, 

 twisted pillar which bears a single distinct fold; body whorl with 

 only a glaze, pillar hardly or not at all thickened ; aperture approx- 

 imately lunate. Lon. of shell, 6*0; of last whorl, 525; of aperture, 

 4-25. Max. lat. of shell, 40; of aperture, 1-62 mill. {Dall). 



Off Bahia Honda, Cuba, 310 fms. (Blake); Off e. coad of the 

 United States 2574 fms. (Verrill). 



Adceon melampoides Dall, Bull. M. C. Z., ix, p. 95, 1881 ; Blake 

 Rep., Gastr., p. 41, pi. 17, f. 2. — A. hebes Verrill, Trans. Conn. 

 Acad, vi, p. 428, pi. 44, f. 15, 1885. 



The A. hebes, which Dall believes to be identical, is shown in fig. 

 12 of pi. 19. 



A. PERFORATUS Dall. PI. 20, fig. 36. 



Shell small, pointed, waxen white, with a narrow opaque yellow- 

 ish band in advance of the suture, composed of about six whorls, 

 and with a distinct umbilical perforation ; nucleus eroded, small ; 

 spire with about six, or (on the last whorl) eighteen strong and very 

 regularly and distinctly punctate grooves, the punctuations at the 

 rate (near the aperture) of about six to a millimeter, the grooves a 

 little more crowded anteriorly and distant posteriorly, the inter- 

 spaces everywhere wider than the grooves and with no intercalary 

 grooves or stride whatever ; transverse sciilptuie of faint lines of 

 growth ; aperture rounded in front, pointed behind; outer lij) thin, 

 simple, arched, and continuous with the reflected thin pillar lip, 

 upon which a fold can hardly be made out ; body with a slight 

 glaze ; umbilical perforation straight, with smooth walls, appar- 

 ently very deep, and about 0'25 mm. in diameter. Lon. of shell, 

 7-75 ; of last whorl, 6-0 ; of aperture, 4 0. Max. lat. of shell, 4*62 ; 

 of aperture, 2*0 mill. (Dall). 



Gulf of Mexico, 805 fms. (Blake). One specimen. 



A.perforatus Dall, Bull. M. C. Z., ix, p. 96 ; Blake Rep. Gastr. 

 p. 42, pi. 18, f. 3. 



It differs from A. exiguas Dkr. of the same region in its very much 

 shorter spire and globular proportions, in its obsolete columellar 

 fold and the strength and uniformity of its punctate sulci. The 

 anterior part of the last whorl being a little larger than any part 

 posterior to it, this shell has a somewhat pyriform appearance. 

 {Dall). 



