6 some m:w and rare diatoms 



as in the larger form, except the three radiant canalieuli are zigzag. Distance between 

 angles .0024 inch. Sprirgfield Estate, Barbadoes. Plate IV, Pig. 10. 



Syndetoeystis Grevffleanne, {Rolfs M. S.) Grev. in litt. 1864. k ' — tin* 

 queerest diatom I have ever had to deal with, a new Genus from the Barbadoes Deposit, 

 which Mr Ralfs describes and which lie calls Syndetocytiss. I have seen five frustules 

 in a chain. The Bide view is a disc with radiating granules or cellules, and from the 

 center projects a strong process which is locked into that of the adjoining disc, like a 

 piece of machinery, so that the two frustules can be pulled asunder to the extent of the 

 Length of the processes, but no further. It seems to be a special provision to prevent 

 separation." Cambridge Estate, Barbadoes. A faithful copy of Dr. Greville's drawing 

 of this most etiange diatom is given in Plate IV, Fig. 13. 



JEntogonin Abercrombieana, Oreo., Mic. J. 1863 p. 9; Sch. At. 85 f. 7= 



Triceratiwm Abercrombieanum, Grev. Trans. M. S. 1861 p. 83 pi. 10 f. 7-9. "Valve 

 with near]}' straight eides ; obtuse angles ; striated margin; centre a blank, triangular 

 Bpace ; border divided by transverse coslae into punctated compartments; a short line 

 from each internal angle terminating in a wide fork with incurved apices ; a faint in- 

 curved line passing through the middle of each border. Pseudo-nodule single, punc- 

 tate : number of marginal costae variable." Distance between angles, .0025 inch. Cam 

 bridge Estate. Barbadoes. Plate III, Fig. 6. 



Triceratiurn iuttigne, Grev., Trans. M. S. 1861 p. 75 pi. 9 f . 5 ; Schm. At. 

 78 f. 3. l> Valve with concave sides; broadly rounded angles furnished with miuutely 

 |.u in late pseudo-nodules ; surface filled with radiating lines of minute granules, except 

 a small circular, central, blank space; margin with short, broad strice, 9 in .001 inch. 

 The appearance of a line separating the angles from the centre is caused by the radiating 

 lines of granules curving up the angle?, and being viewed in perspective: these radiant 

 lines of grannies do not quite reach the margin. Distance between angles, .0024 to .0035 

 inch Cambridge Estate, Barbadoes. Plate III, Fig. 7. 



Entogonia margiviata, (BrigJdwell), Grev. Trans. M. S. 1863 p. 10: Schm. 

 At. 88 I. 6; .lour. X. Y. M. S. 1886 p. 110 pi. 4 f. 2 := Trie, marginatum, Bright- 

 well, M. J. 18.56 p. 276 pi. 17 f. 13; Trans. M S. 1760 p. 148 pi. 7 f . 4 ; 1861 p. 4 pi. 10 

 f. 5; Pi it. Inf. ]). 854. Valve with convex sides; rounded angles; double pseudo-no- 

 dnles; inner triangle with three radiant lines extending from centre toapices, from which 

 linesa Dumber of radiant, nodulose, capita tecostrc proceed to the margin; border of valve 



