898 TransacUons of the Society. 



14. Markings obscure. Processes 4 parvulus. 



„ DJinule, punctate. Processes 2, close to major axis, nitidus. 



15. Transverse areas faint 16 



„ „ distinct 17 



16. Apiculate 18 



Non-npiculate, a delicate reticulum witli small raesbes evident graciUimus. 



18. Apiculi aggregated on a narrow band around each process .. pectinutus. 



„ few, minute, between outer edges of transverse areas 



and the areas between the centre and processes .. 19 



19. Transverse area narrow, with clavate outliTie eximius. 



„ „ widening towards border with irregular outline antiquus. 



17. Transverse areas, with concave or straight ends and obscure 



markings iusignis. 



„ „ with convex ends and evident markings ; 



pearly areola) forming a marginal band 

 and V-shapcd lines on the central side of 



each process decoratus. 



Appearance otherwise 20 



20. Markings sctibrous. Transverse areas narrow towards the 



centre, their outer ends suddenly expanding, 



rounded hardmanianvn. 



y, delicate. Transverse areas expanding widely out- 



wards. Processes large, high, with sides concave 



and apices convex Biddulphia. 



„ delicate. Convolute anastomosing clear lines be- 



tween transverse areas and those extending 



between central space and processes intestindlit. 



13. Central space elongately elliptical. Transverse areas oblique 



to direction of processes raeanu». 



„ „ indefinite. Transverse areas defined by a clear 



band. Markings small, round, granular, in 



radial rows beyond tins band pauper. 



„ „ round or angular 21 



21. No transverse median areas 22 



Transverse median areas present 23 



22. A reticulum 24 



Reticulum almost confined to central portion of valve .... 25 



No reticulum 26 



24. Eeticulum with small subregular meshes, central portion of 



valve not diti'erentiated from peripheral .. .. texiilis. 

 „ coarse, irregular, outline of central portion extending 



between sides of processes faint stibreticulatus. 



„ irregular, distinct only outside of sharply defined 



central portion. Processes 4 speciostis, 



25. Central portion of valve distinct 27 



„ ,, „ indistinct, regularly rounded, a re- 

 ticulum with small delicate meshes 

 chiefly on its outer part spectabilis. 



27. Central portion regularly rounded, not reaching central side 



of processes Schmidtii. 



„ „ extending round outer side of processes and 



pr(jtruding opposite the central space . . reticulatus. 

 „ „ elliptical, not protruding opposite the central 



space compositus. 



26. Central portion indistinct t8 



„ „ distinct 29 



„ „ undifferentiated 30 



28. Central portion continued round outer side of processes. 



Markings obscure striae lucidus. 



„ „ extending to processes, between these its 



sides reaching close to border. Markings 



minute, punctate sublievis. 



„ „ extending to processes, its sides between these 



concave outwards. Processes 4 ojiuhntus. 



29. Outline of central portion hourglnss-shaped 31 



« „ „ not hourglass-shaped 32 



