AKT. 18 SMALL SHELLS DEEDGED BY '' ALBATROSS * ' DALL 71 



ACLIS TENUIS VerrUl 



Aclis tenuis Verkill, Trans. Conn. Acad., vol. 5, p. 528, pi. 58, fig. 19, 1882. 



Off Georgia, nine specimens. Off Marthas Vineyard, 100 fathoms, 

 United States Fish Commission. 



ACLIS CUBANA Bartsch 



Aclis cubana Bartsch, Proc. U. S. Nat. Mus., vol. 40, No. 1829, p. 435, 

 pi. 59, fig. 2, 1911. 



Off Fernandina, 20 specimens. Off Cuba in 780 fathoms mud; 

 Dr. W. H. Rush. 



ACLIS RHYSSA, new species 



Shell small, slender, subcylindrical, translucent white, polished, with 

 nine or ten well rounded whorls; the apex blunt, the nuclear whorl 

 small and slightly tilted, suture constricted; axial sculpture of numer- 

 ous (on the last whorl about 15) somewhat sharp wrinkles, strongest at 

 and behind the periphery where they sometimes give an obscurely 

 angulate appearance just behind the middle of the whorl, and are a 

 little retractively flexuous; the strength of these wrinkles varies in 

 different specimens, some of them are nearly smooth on the later 

 whorls; the base is evenly rounded and imperforate; the aperture 

 ovate, with thin margins. Length of type specimen, 6; diameter, 1.3 

 mm. U. S. Nat. Mus. Cat. No. 108389. 



Off Georgia, very numerous. Off Fernandina, one specimen. 



This species is somewhat like A. dalli but more cyHndrical and with 

 more constricted suture, while A. dalli has no axial sculpture except 

 faint incremental lines. 



ACLIS HENDERSONI, new species 



Shell small, translucent white, with two transparent apical whorls 

 and seven subsequent whorls; suture deep; early whorls with two 

 peripheral elevated threads, later four, then on the last three whorls 

 the posterior thread becomes a well defined keel at the shoulder 

 while the other threads become obsolete; base well rounded, imper- 

 forate; axial sculpture of faint incremental lines; aperture obHquely 

 ovate, the peristome expanded and even somewhat reflected, thin 

 and simple. Length, 4.3; last whorl, 1.7; diameter, 1.3 mm. U. S. 

 Nat. Mus. Cat. No. 333465. 



Off Fernandina and Georgia, one specimen each. 



This recalls A.Jloridana Bartsch, but is larger and with much more 

 emphatic sculpture. The young shell is spirally threaded over the 

 base and on the last whorl. 



Subgenus x\MBLYSPIRA Dall 

 ACLIS (AMBLYSPIRA) IMMACULATA, new species 



Shell minute, subcylindrical, polished, white with a blunt apex 

 and about six nearly flat-sided whorls; suture obscure, flatly appressed, 



