110 BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



The following five species of Cadulus may be placed together by 

 reason of all possessing relatively large apical orifices: C. agassizii, 

 0. catharus, 0. parvus, C. foweyensis, 0. portoricensis. 



CADULUS (PLATYSCHroES) AGASSIZII Dall. 



Plate 18, figs. 1, 3. 



1881. Cadulus ajassizii Dall, Bull. Mus. Comp. Zool., vol. 9, p. 35. 



1889. Cadulus a/assizii Dall, Bull. Mus. Comp. Zool., vol. 18, p. 430. 



1889. Cadulus ajassizii Dall, Bull. 37, U. S. Nat. Mus., p. 78, pi. 27, fig. 12 (c). 



1898. Cadulus (Gadila) a-assizii, Pilsbry and Sharp, Tryon's Man. Conch., vol- 



17, p. 168, pi. 25, fig. 57. 

 1898. Cadulus ajassizii hatterasensis Pilsbry and Sharp, Tryon's Man. Conch., 



vol. 17, p. 169, pi. 33, figs. 50-54. 



The shell is fairly solid, moderately curved, and having its maxi- 

 mum diameter, which is not bulbous, at about the anterior third. 

 The anterior aperture is constricted, oblique, and round. The apical 

 orifice is slightly flattened and conij^aratively large, olten seemingly 

 as large as the other aperture. The convex arc is almost flat along 

 the anterior half of the shell and is slightly bulged out at its point of 

 maximum diameter. The swelling, however, is a gradual one and 

 unmarked by any prominent equator or angle. Posteriorly the shell 

 is not much attenuated, but terminates in a large, open, and slightly 

 flattened apical orifice. The apical features consist of four very 

 broad, shallow slits that form as many indistinctly marked lobes; 

 the one on the concave side is the broadest, the lateral ones being 

 reduced to mere points; the dorsal one is rather broad and bluntl}^ 

 pointed. In many specimens, however, only the lateral points on 

 the rim of the apical orifice are noticeable. Measurements are: 



Length, 9 mm. ; maximum diameter, 2 mm. ; anterior aperture, 1.25 

 mm.; apical aperture, 0.75 mm. (type) 



Length, 8.75 mm.; maximum diameter, 1.75 mm.; anterior aper- 

 ture, 1.10 mm.; apical aperture, 0.75 mm. (Sand Key). 



The type is in the Museum of Comparative Zoology, Cat. No. 7746, 

 and was taken by the Blake at LTnited States Coast Survey Station 5, 

 south of Marquesas Key, Florida, in 229 fathoms, bottom temperature 

 49.5° F. 



This is a very abundant species in the Florida Keys region in from 

 75 to 299 fathoms, and also from the Hatteras region in from 87 to 

 293 fathoms {^^ Cadulus agassizii hatterasensis^'). 



About 80 lots containing many hundreds of excellent specimens 

 from the Gulf Stream edge along the lower Florida coast which have 

 recently been received, together with some additional lots from the 

 Hatteras region now in the museum collection, make possible a closer 

 study of this species than was heretofore the case. The lack of suf- 

 ficient characters to maintain Doctor Pilsbry's subspecies is evident. 

 C. agassizii has not the bent " dog tooth" aspect of C. pandionis, with 



