Ctrkvillr, on New Diatoius. 43 



Hab. Barbadoes deposit; rare. 



A very delicate, transparent little disc, easii}^ overlooked, 

 but well marked by its wide fringe-like rays. 



Coscinodiscus Barbadensis, n. sp., Grev. — Disc divided into 

 compartments by double lines of punctiform cellules, tiie 

 intervals between the lines being so clearly defined as to pre- 

 sent the appearance of rays; cellules within the compart- 

 ments less conspicuously radiate, subequal, except at the 

 margin; 15 in 'OOl'' ; diameter of disc •0025". (Fig. 9.) 



Hab. Barbadoes deposit ; very rare. 



Disc convex, very delicate, and apt to be overlooked even 

 by careful observers. Under a moderately magnifying pow^r 

 it would scarcely be taken for a Coscinodiscus, as it rather 

 suggests the idea of an Actinocyclus (Ehrenberg, not Smith) ; 

 but, under a higher power, the apparent rays are found to re- 

 sult from the space left between two lines of cellules, which 

 radiate from the centre to the circumference. Further ob- 

 servations may determine the presence of an umbilical pore. 

 One of my specimens is injured at that part; and the other 

 shows, although obscurely, an approach to such a character. 



Triceratium. 



Triceratium capitatum, n. sp., Ralfs. — Valve with the 

 angles much produced and capitate, and separated from the 

 centre by a transverse line ; surface with indistinct, scattered 

 puncta, and two spines. Distance between the angles about 

 •0019". (Fig. 10.) 



Hab. Barbadoes deposit; extremely rare. 



" A small species, with very indistinct puncta. Valves, 

 irrespective of the produced angles, straight or slightly con- 

 vex." (Ralfs.) The frustule appears to be not unfrequently 

 imperfect or mutilated. 1 had examined half a dozen ex- 

 amples before I perceived any trace of puncta at all. Mr. 

 Rylands then kindly communicated a specimen, in which, in 

 addition to the central puncta, a few larger and more definite 

 puncta were scattered on the narrow portion of the produced 

 angles, and the surface was also furnished with two conspi- 

 cuous spines. I have subsequently found two frustules 

 myself, exhibiting very distinctly these characters. 



Tricei'atium Westianum, n. sp., Grev. — Sides of the valve 

 deeply and sharply concave; angles forming segments of 

 circles, separated from the centre by transverse lines ; margin 

 of the angles with very short radiating lines ; surface strongly 

 punctate; distance between the angles -0018." (Fig. 11.) 



Hab. Barbadoes deposit ; extremely rare. 



