EAST AMEKICAK SCAPHOPOD MOLLUSKS. 143 



The type, in the British Museum, is from the same Challenger sta- 

 tion as of C. curtus (24), off Culebra Island, West Indies, in 390 

 fathoms, bottom of Pteropod ooze. 



I have seen no specimens and can not refer to the species with cer- 

 tainty any specimens in the National Museum. The fact that it is 

 not a compressed shell, as is C. curtus, and that it is also one-third 

 larger, seems sufficient evidence to warrant a specific separation. 



CADULUS (CADULUS) TRANSITORIUS, new species. 



The shell is very small, quite inflated, its greatest diameter being 

 about median, but the equator is without any local swelling; the 

 cvlinder is decidedly compressed laterally, giving to the oblique aper- 

 ture a somewhat oval outline, but the apical orifice is round, or m a 

 subspecific form very slightly flattened. The convex outline forms 

 a reo-ular arc without irregularities at any point; the concave out- 

 line is actuafly concave only anteriorly, is bulged out at the equator, 

 and is a straight line posteriorly. The apical orifice is somewhat 

 constricted, but remains relatively large for the genus, and is girdled 

 within by a circular shelf, showing from without as an internal white 

 callous ring The apical features are simple. Measurements are: 



Leno-th, 3 mm.; diameter, 0.90 by 0.75 mm.; anterior aperture, 

 5 mm. ; 'apical aperture, 0.4 mm. ( type of typical subspecies) . 



Length 3.5 mm.; diameter, 0.9 by 0.8 nun.; anterior aperture, 0.5 

 mm.; apical aperture, 0.4 mm. (type of C. t. harhadensis) . 



This little Cadulus may eventually be connected by intermediates 

 with C verrilU, and thus be shown merely to constitute a southern 

 race of that northern Gulf Stream species. It has, however, a more 

 inflated shell than has C. verrilli and seems to stand upon the border 

 line between the subgenera GadiU and Cadulus. I have included un- 

 der the name a number of lots that vary slightly from the type, as I 

 dislike to multiply the species of these minute Caduli without more 

 abundant evidence. A lot from Old Providence is more particularly 

 aberant in having the inflation more localized. These with Cverntt^ 

 a atlanticus, and C. mayori resemble the species of a European group 

 represented by C. jeffreysi Monterosato, and includmg G- ^^ac^^ 

 Jeffreys and C. propinquus Sars; but a careful comparison with 

 authors' examples of these eastern Atlantic forms convmces me of 

 their specific differences, although superficiafly they appear to be so 

 very much alike. On the other hand, it bears close affinities with 

 the group of bulbous species under the subgenus Cadulus, and among 

 which I believe it should be placed. 



CADULUS (CADULUS) TRANSITORIUS TRANSITORIUS. new subspecies. 



Plate 19, fig. 6. 



' The shell of this, the typical subspecies of Cadulus transitorius, is 

 described under the heading of that species. It mcludes. however. 



