EAST AMERICAN SCAPHOPOD MOLLUSKS. 149 



A single specimen in the lot is smaller — length, 4.2 mm.; diameter, 

 1.1 mm., but otherwise agrees. 



Topotypes, a lot of two specimens, Cat. No. 314935, U.S.N.M., 

 dredged by the State University of Iowa Expedition at station 115, 

 off English Harbor, Antigua, in 120 fathoms, are the only specimens 

 in the National Museum collection. 



CADULUS (CADULUS) HALIUS, new species. 



Plate 20, fig. 12. 



The shell is small, rather inflated, with a median equator, rather 

 short and somewhat flattened, with an oval apical opening. The 

 *'neck" or posterior end is contracted, though not abruptly so. 

 The convex outline posteriorly is a little concave, but is very convex 

 over the bulging median portion and very slightly convex anteriorly. 

 The concave outline is modified by a convex bulge in the median por- 

 tion. The median equator is not marked by any carination. The 

 anterior aperture is small and oblique. Sgme opaque rings within 

 the apical orifice are quite noticeable. Apical features are simple. 



The type is in the collection of the State University of Iowa, and 

 measures — length, 5.5 mm.; diameter, 1.3 mm.; anterior aperture, 

 0.6 mm.; apical aperture, 0.5 mm. It was dredged off English Har- 

 bor, Antigua, in 120 fathoms. 



This species resembles Cadulus podagrinus in several features, but 

 lacks the exaggerated humpbacked appearance. The bulbous por- 

 tion of the shell more slowly contracts into the pinched-in neck and 

 has a more median position of the equator. Although the two species 

 inhabit the same localities, there are no intermediates among the 

 specimens before me. 



Cotypes, a lot of four specimens. Cat. No. 314936, U.S.N.M., were 

 obtained by the State University of Iowa Expedition of 1918 at 

 station 115, in 120 fathoms, off English Harbor, Antigua. 



CADULUS (CADULUS) TERSUS, new species. 



Plate 20, fig. 4. 



The shell is small, rather strongly curved, with very small aper- 

 tures. The equator is slightly anterior to a median position and 

 marks a pronounced local swelling. The convex outline describes an 

 even deep arc; the concave outline has a convex bulge at the equator. 

 The neck or posterior portion is quite long and round, ending in a very 

 small round apical opening. The anterior aperture is not oblique, 

 but is slightly oval, the anterior portion of the shell being a little 

 flattened dorso-ventrally. Just within the apical orifice is a callous 

 ring. The lateral outlines viewed dorsally or ventrally taper evenly 

 from the equator to the small ends, giving a fusiform shape to the 

 cylinder. The apical features are simple. 



