DENTALIUM-FISSIDENTALIUM. 73 



Dall has already announced the specific identity of D. candidum 

 Jeffr., solidum Verrill and ergasticum Fischer. Jeffreys' specimens 

 of D. candidum prove on comparison to be absolutely the same as 

 the young D. solidum Verrill, though the snowy whiteness of the 

 original specimens, with their rather narrower, sharper riblets as in 

 all young shells of the species, give them a different aspect at first 

 view from the drab or ashen, obsoletely sculptured adult shells 

 dredged in American waters. The glistening white color is proba- 

 bly due to local conditions ; Dall remarks : " Under favorable cir- 

 cumstances this species may be of a most brilliant milk-white, but 

 nearly all the specimens are dull ashy-gray in color, even when liv- 

 ing and in perfect order. I suppose the white ones are those which 

 happen to live in pure sand, while the ordinary form comes from 

 mud or ooze." The young of one lot collected by the " Albatross " 

 240 miles E. by S. of Rio Janeiro, are as pure white as Jeffreys' 

 types. 



Var. MERiDiONALE Pilsbry & Sharp. PI. 15, figs. 32, 33, 34. 



Off Brazil the shell becomes larger and still more solid, the strise 

 more numerous (90 or more), and they j^^'t'sist to the aperture, not 

 becoming obsolete on the later portion of the tube. The aperture 

 is more or less compressed between the convex and the concave 

 sides. Specimens measure : 



Length 101, diam. of aperture, transverse, 12-8, longitudinal 123 

 mill.; length of slit 3 mill, (type, no. 87,557 U. S. Nat. Mus.). 



Length 108, diam. of aperture, transverse, 14 mill, (off Rio 

 Janeiro). 



Length 110, diam. of aperture, transverse, 11, longitudinal 10 

 mill, (near Jamaica). 



The specimens from near Jamaica and from off Cape Fear are to 

 some extent intermediate, but nearer to the variety than to typical 

 D. candidum (solidum'). In our opinion the Atlantic shells referred 

 to D. ceras Wats, by Dall are the young of this large southern race 

 of D. candidum. Figures 33 (enlarged) and 34 (natural size) show 

 the variation in development of the apex. We repeat here the orig- 

 inal description of candidum. 



B. candidum Jeffreys. PI. 8, fig. 29, 30. 



Shell having the shape of a narrow funnel, tapering, slightly 

 curved, rather thin, opaque, more or less glossy. Sculpture, about 

 forty fine and regular rounded longitudinal strise, which disappear 



