296 CYLICHNA. 



prominent ; spiral sculpture consisting of very numerous fine grooves, 

 so crowded near the ends of the shell as to be but little narrower 

 than the interspaces ; these grooves are only visible under a lens, 

 are occasionally reticulated by the lines of growth and gradually be- 

 come more distant toward the middle of the shell ; just in advance 

 of the shoulder of the bevel are a small number of equally fine raised 

 lines, which are so minute that only by the most careful inspection 

 and under strong magnification can they be distinguished from the 

 grooves which cover the rest of the shell : the folds of the outer 

 whorl are appressed toward the apex, with a somewhat thickened 

 and irregular margin, which leaves a minute pit at the summit and 

 about two volutions visible ; this appressed margin is often eroded, 

 and then some four or five turns can be made out ; in advance of 

 the bevel the shell is nearly cylindrical, rather suddenly rounded in 

 front; outer lip straight, slightly produced in the middle, but not 

 bent inward toward the body ; passing imperceptibly into the column, 

 over which, as well as over the body, is a thin layer of callus. Aper- 

 ture rounded and rather wide in front, narrowing to an acute point 

 behind, shorter than the shell ; pillar with no twist or fold, contin- 

 uous with the margin. Lon. of shell, 7'5 ; of aperture, 6'0. Max. 

 lat. of shell, 4'25 ; of aperture, 2'5 mill. (Dalf). 



East of George's Bank to of Chesapeake Bay, 326-1356 fms. 



Utriculus ? vortex DALL, Bull. M. C. Z. ix, p. 100, 1881 ; Blake 

 Gastr., p. 47, pi. 17, 3, 1889. Cylichna vortex BUSH, Bull. M. C. 

 Z. xxiii, p. 221. 



After comparing this with the figures of all the Northern species 

 given by Sars and those from the West Indies by d'Orbigny, it 

 seems quite distinct from any of them. It is possible that it may 

 prove to be a Cylichna when the animal is known ; but it does not 

 agree with any of the figured Cylichna. (Dall). 



In studying the specimens labelled Cylichna dalli in 'the Fish 

 Commission collection I found some confusion in the identification, 

 and that two similar but distinct forms had been placed under that 

 name : Cylichna dalli Verrill, and Cylichna vortex Dall. The differ- 

 ences in the two species are clearly shown in the figures quoted 

 above. C. dalli is most readily distinguished by its " strongly ex- 

 cavated and sinuous " columella, which forms anteriorly a distinct 

 fold or tooth-like projection where it joins the strongly curved 

 outer lip ; while C. vortex has a gently curved columella, passing 

 " imperceptibly " into the outer lip without " twist or fold." 



