SOME NEW AND KA1IE DIATOMS. 



Trie, cancellation, var. minor, W. and C — Small ; sides straight, angles acute 

 and slightly produced, with a small, blank nodular space ; surface covered with large 

 areola?, irregularly disposed in the centre, but arranged in parallel rows in the wide 

 border, extending to the margin ; the areohe irregular or quadrangular in outline. Dis- 

 tance between angles, .0024 inch. Cambridge E^ate, Barbadoes. Plate III, Fig. 16. 



Grunow mentions a small variety of T. cancellalum, Grev.. in his " JMovara Al- 

 gen," but likens it to Trie, obtusum, Ehr. As there is no point of similarity between 

 these two species, except in their triangular outline, our variety takes its name. 



Trie. nu'ni(ttnn, N. Sp., W. and, C. Small ; sides straight ; angles obtuse; 

 surface sparsely cellulose ; margins smooth ; no nodule at angles ; distance between 

 angles, .0010 inch. Springfield Estate, Barbadoes. Plate IV, Fig. 35. 



Cestodiscits Sttyerhtts, Hardman, Cole's studies, 1886, p. 49, cum Photo. — 

 Valves of frustule dissimilar in areolation, but alike in marginal border ; in one, the 

 central area is concave, with brilliant, scattered, hemispherical beads becoming fewer 

 toward the center, which is sometimes a blank space ; the other valve is convex, with 

 closely set rows of large, somewhat angular granules radiating from a minute central 

 bead. Some of the frustules are concavo-convex, some bi concave some bi- convex. The 

 fine stria tion of the margin is diagonal in character, as well as radiant, and simulating, 

 upon a coarser scale, the peculiar "eDgine turning" markings of Hyalodiscus subtilis. 

 Diameter of disc, from .0027 to .0045 inch. Newcastle Estate, Barbadoes. Plate V, 

 Fig 14, 15. Both the figures here given present the convex valve, and show the varia- 

 tion in areolation ; the cellulation of the opposite valve is always of the character above 

 described, and we will in our next series give a figure of the concave valve. 



The Diatomacese described in the foregoing pages are from a collection of the Barba- 

 does fossil marine deposits that come into our possession some three years since. 



