414 DISCOVERY REPORTS 



umbilical area, within which the aperture, a loop-shaped slit, is situated under the inner 

 edge of the final chamber. The sutural lines on the ventral side are short, nearly straight, 

 and slightly depressed ; the peripheral margin is sub-acute with a narrow, thickened edge 

 on the dorsal side. Texture of the shell whitish, and opaque like ground glass on the 

 dorsal side, very hyaline on the ventral side. 



Length of largest specimens up to 0-30 mm.; breadth, 0-20 mm.; height, o-ic mm. 



Seven specimens of this very distinctive species were found at WS 88, and single good 

 specimens at 388 and WS 92. It is quite unlike any other species known to us in the 

 paucity of chambers forming its spiral. 



345. Discorbis bertheloti (d'Orbigny). 



Rosalina bertheloti, d'Orbigny, 1839, FIC, p. 135, pi. i, figs. 28-30. 

 Discorbina bertheloti, Brady, 1884, FC, p. 650, pi. Ixxxix, figs. 10-12. 

 Discorbis bertheloti, Cushman, 1910, etc., FNP, 1915, p. 20, pi. vii, fig. 3. 



Fifteen stations: 51, 388; WS 71, 77, 83, 86, 87, 88, 89, 90, 97, 99, 221, 245, 408. 



Widely distributed but never very common. The best and most typical specimens 

 occur at the range of stations WS 83-88, very fine at WS 86, and equally good at WS 221 

 and 245. The Paris Type is missing. 



346. Discorbis bertheloti var. baconica, Hantken. 



Discorbina baconica, Hantken, 1875, CSS, p. 76, pi. x, figs. 3 a, b. 



Discorbina baconica, Brady, 1884, FC, p. 651, pi. xc, fig. i. 



Discorbina bertheloti var. baconica, Heron-Allen and Earland, 1916, FSC, p. 50, pi. viii, figs. 



10-12. 



Six stations: 388; WS71, 86, 88, 91, 92. 



This limbate variety is very much rarer than the type, but excellent specimens occur 

 at 388 and WS 86, and one, extraordinarily limbate, at WS 91. 



347. Discorbis bertheloti var. complanata, Sidebottom (Plate XIV, figs. 17, 18). 

 Discorbina bertheloti var . complanata, Sidebottom, 1918, FECA, p. 253, pi. vi, figs. 1-3. 



One station: WS 88. 



A few specimens only. 



348. Discorbis valvulata (d'Orbigny). 



Rosalina valvulata, d'Orbigny, 1826, TMC, p. 271, no. 4; 1839, FIC, p. 136, pi. ii, figs. 19-21. 

 Discorbis valvulata, Cushman, 1921, FNCJ, p. 59, pi. xiv, figs. 4-5. 



One station: 51. 



One fairly typical specimen. The species appears to be widely distributed. The Type 

 is missing. 



