Tribe XXI. Biddulphie/E. 



f Valves unlike ; frustutes with one neck-like process, generally oblique, cohering irregularly . 





d 

 > 



r 





0) 



'5 



in a; 



o d 



q C 



^2 



3 3 



d 

 > 



Frus- 



tules 

 scarcely 

 silicious. 



o 

 d 



o 



d 

 > 



Valve 



oval, 



elliptic. 



Apices 



raised 



on the 



j major 



] diameter 



Apices terminating in a hood 



Apices ter- ( Processes of equal length 

 minating in a j 



point or "i, Processes of unequal length 



1, mucron. (_ frustules cuneate 



I Margins r: 

 [_ distinct v 



aised on the minor diameter 

 umbilicus 



valve with small 



v , , f Valve triangular, furnished with three processes 

 L 3 ' v. Valves quadrangular, furnished with four processes 



Apices not raised, no mucron ; valve oval elliptic 



Apices with capitate [ Valve linear-lanceolate, with several constric- 

 septa in girdle view, tions , 



d 



a 



e 5 

 > a - 



O m 

 in 



and resembling 

 musical notes. 



Valves 

 with 



scalari- 

 form 



septa. 



v Valve with three processes like nipples 



a! 

 > 



Frus- 

 tules and 

 valves 

 not as 

 above. 



r 



Valves 



not 

 arcuate. 



Valves composed of numerous joints, 

 cells, or pseudo-cells ; gradually 

 diminishing from the median, 

 which is very large 



Valves elliptic or with straight apices 



Valves vermiform, sigmoid 



Valves arcuate .... 



' Valves triangular, septa numerous, in the centre 

 of the valve a triangular figure, with different 

 striation .... 



Isthmia. 



Baxteria. 



Hemiaulus. 



Corinna. 



Graya. 



Trinacria. 



Solium. 



, Ploiaria. 



Terpsinoe. 

 Hydrosera. 



Pseudo-Rutilaria. 



Auaulus. 



Helminthopsis. 



Eunoiograrunia 



Septa 



not 



scalari- 



form. 



Valves 

 not 



triangu- 

 lar, 

 septa 

 few. 



Valves oblong, with inflated centre, 

 and apices raised into obtuse 

 processes 



i 



| Valves arcuate, with 2-3 septa, some- 

 times absent or obscure. Puncta 

 (_ very coarse, radiant . , 



d 

 C 



r Valves elliptic circular, 3, 4, or 5 angular, etc., having elevated obtuse pro- 

 cesses at the apices and sometimes also simple horns 



' Valves elliptic, showing four elevations and transverse and 

 radiant hyaline spaces (canaliculi ?) . 



f Valves showing 7-8 elevations, mammiform and 

 marginal .... 



2 a -[ 



a a I 



in 

 V 

 > 



"d 



> 



Valves 

 not as 

 above. 



Valves 

 not as 

 above. 



Entogonia. 



Porpeia. 



Euodia. 

 Biddulpnia 

 Tabulina. 

 Grovea. 



Valves showing two elevations alternating with 

 ocelli . . . . . 



Huttonia. 



Valves furnished with spinous ridges Odontotropis. 



fur- often bifurcated, horns Keratophora 



above 



1 



peculiar I 

 I. horns. L 



Filament twisted round itself like a cork-screw.- Valve without processes 



nished 1 



with j Valves bearing long 



peculiar I horns, terminating in 



horns. I cup-shaped expansion 



Filament not 

 twisted spirally. 



Frustules with 



processes short, 



obtuse ; valves 



without awns. 



f Valves with two ( Filament curved spirally 

 I processes obscure < 



or absent. I Filament straight 



Valves with three processes, filament straight 

 I. Frustules furnished with robust awns , , 



Kittonia. 



Streptotheca. 



Eucampia. 



Climacodium. 



Bellerochea. 



Lithodesmium. 



