168 



Amphipentas obtusus, Bail., nov. sp. 



Sides five, concave ; angles conical and rounded ; lateral surfaces 

 slightly concave, minutely granulated ; connecting membrane punctate 

 in parallel vertical rows. Differs from A. jftexuosa, B. MS. in the 

 sides being concave instead of gibbous. 



Hab. lat. 0° 19' 05^' K ; long. 45° 43' 36'' W. 



Cyclolella ? PULCHELLA, L. W. B., nov. sp. 



Disc small, with a central umbo, from near the base of which 

 radiate (16) dilating styliform rays. Margin with large granules, 

 corresponding to the rays. 



Hab. lat. 1° 01' 29" N.; long. 46° 17' 46" W. 



BiLOCULIXA 6ERRATA, Bail., nOV. Sp. 



Smooth, opaque, porcellaneous, globose, with serrated margin, which 

 is distinct on the under side, and indistinct on the upper. 

 Hab. Gulf Stream, 150 fathoms. 



Cymatopleura ? Campylodiscus, Ban., nov. sp. 



Large ; lateral view almost circular, sometimes broadly oval. 

 Marginal stride close, short, and showing under high powers marginal 

 glandlike dots. Lateral valve with one deep undulation. 



Hab. Honey lake valley, foot of Sierra Nevada. 



Cymbella gibba. Bail., nov. sp. 



Small; valves with very convex, almost conical dorsum, and 

 slightly convex venter ; striae fine and close. 

 Hab. Honeylake Valley, Sierra Nevada. 



The two following forms have been detected by me, the first in 

 soundings off Key Biscayne, Fa., the second in rough material from 

 the Para. They are here introduced for the sake of comparison, with 

 the two species of Syringidium previously described. 



Syringidium cucullatum, L. W. B., nov. sp. 



Frustules small, balloon-shaped and punctate ; valves unequal, one 

 consisting of a turgid semiglobose cap, armed with two stout pro- 

 cesses, the other of an undulate pyramidal cone. No spines or 

 mucro. 



Hab. Gulf Stream. 



Syringidium Paraense, L. W. B., nov. sp. 



Frustules minute, punctated ; central portion quadrangular ; valves 

 unequal, one with a circular base, suddenly contracted, and again 

 expanded into a conical form, armed near the apex of the cone with 

 two processes ; the other valve suddenly contracted and tapering, 

 into a pjTamidal spine terminated by a mucro. 



