EAST AMERICAN SCAPHOPOD MOLLUSKS. 105 



CADULUS (PLATYSCHroES) GRANDIS Verrill. 



Plate 17, fig. 12. 



1884. Cadulus grandis Verrill, Trans. Conn. Acad, of Arts and Sci., vol. 6, pt. 1, 



p. 219, vol. G, pt. 2, pi. 44, fig. 20. 

 1898. Cadulus (Polyschides) grandis, Pilsbry and Sharp, Tryon's Man. Conch., 



vol. 16, p. 154, pi. 25, fig. 66. 



The shell is large, solid, senile specimens becoming thick and heavy, 

 moderately curved, the curvature mostly in the posterior portion. 

 The convex arc is quite regular to a point about one-third distance 

 from the anterior aperture, thence to the anterior end the arc is more 

 accelerated. The concave arc is greatest posteriorly, the last hall 

 of it being almost straight, and shows a very slight convexity at the 

 anterior third or fourth section, that being the point of maximum 

 caliber. The posterior aperture is large, giving the shell a ''stumpy" 

 appearance, even though the swelling at the anterior third or fourth 

 is not very great. The anterior aperture is broadly elliptical and 

 oblique and has its margin rounded in fully adult specimens. There 

 are four apical slits, which are rounded and shallow, as compared 

 with those in Cadulus quadridentatus, and leave broad flat lobes, the 

 widest of which is on the convex side. The edge of this lobe is dis- 

 tinctly serrated, but all apical characters are usually more or less 

 obliterated by accidental breaks. The lobes are also somewhat 

 thickened within. Measurements are: 



Length, 15 mm.; maximum diameter, 3.5 mm.; anterior aperture, 

 3 by 2.5 mm.; apical aperture, 1.3 mm. (type). 



Length, 14 mm.; maximum diameter, 3 mm.; anterior aperture, 

 2.3 by 2 mm.; apical aperture, 1.2 mm. (U. S. B. F. Station 2217). 



The type, Cat. No. 34735, U.S.N.M., was taken at U. S. B. F. 

 Station 2076, oft* Marrtha's Vineyard, in 906 fathoms, bottom of blue 

 mud. 



This is a deep-water species from oft' Georges Bank toUatteras in 

 S43 to 1,467 fathoms, and was dredged by the Albatross at numerous 

 stations, as shown by the appended table of lots in the museum col- 

 lection. 



This is one of the largest of the species of Cadulus. Some senile 

 specimens exhibit a chalky texture beneath a glazed surface — a 

 feature already noted in several of the abyssal Dentalia of the north 

 Atlantic. It is easily recognized by its large size and "stumpy" form. 



Num- 

 ber of 

 speci- 

 mens. 



Cat. No. 

 U.S.N. M. 



3473.5 

 34735 

 50333 

 35184 

 38669 

 78233 



Locality. 



Off Martha's Vineyard, V. S. B. F. Station 2076. 



Otf Georges Bank, U. S. B. F. Station 2076 



Otf Georges Bank, U. S. B. F. Station 2530 



Off fJeorges Bank, U. S. B. F. Station 2084 



Off Nantucket Siioals, U. S. B. F. Station 2217. .. 

 Off Nantucket Siioals, U. S. B. F. Station 2710. .. 



1 Type. 



Remarks. 



906 fms., bu. m. 



Do. 

 956 fms., gy. oz. 

 1,290 fms., 40° bu. m. s. 

 924 fms., 38° gy. m. 

 984 fms., gn. m. 



