118 BIOLOGY OP THE RICHMOND RIVER, 



Lismore(2b), with var. producta Grun. 



From Van Heurck's figures, Diat., PI. 9, figs. 359, 360, 361, 

 there would not appear to be any specific difference between E. 

 miLSCulus Kiitz., and E. gibberula var. producta Grun., nor are 

 Kiitzing's figures of the types, Bac, PL 30, f . 3, 6, sufiiciently 

 different for distinct species. In these latter, the lower figures 

 in each case are not of frustules seen in girdle-view, but repre- 

 sent the two outer and opposite valves of a hemisphere of frus- 

 tules cohering after division. The same is true of Van Heurck's 

 figures, Diat., PI. 30, f.825 {sinistra). E. gibberula has priority, 

 as Kiitzing refers it to Ehrenberg. 



Epi. Sorex, E. zebra, E. turgida var. grauulata, and E. gibba 

 var. ventricosa were also abundant both at Lismore and Casino. 

 The three last from Kyogle also. 



Genus Eunotia Ehr. 

 EuNOTiA FORMICA, var. RiCHMONDiiE, n.var. (PI. iv., f.31, 32). 



Valvie levissime arcuatas, medio apicibusque subito inflatse 

 lateribus plus minus parallelis; apicibus acuminatis cuneatis. 



Long. 56-124; lat. valv. 8-9, inflation. 10-14 /x. 



Lismore (3, 6, 12,17,18, 22). 



Forming long ribbons, in company with Eun. depressa Ehr. 

 The latter is the only other form of Eunotia in the river, long. 

 24-96, lat. 8, ap. 5 /x, very common; cf. Kiitz., Bac, PI. 30, the 

 two unnumbered examples between figs.l and 2. 



Genus Synkdka Ehr. 

 Synedra Lismorensis, n.sp. (Pi. iv., f.33-38). 



Valvye in medio constrictse, papilla minuta etiam nonnunquam 

 ornatse; superne interdum paullo inflatpe, ad apices attenuata3) 

 apicibus rostratis. Striis tenuissimis circ 12 in 10 /x, in medio 

 mancis. Latere cingulato frustulum rectangulare, interdum 

 apices versus modice attenuatum, parte non striata ad angulos 

 incrassata. 



Long. 22-88; lat. valv. 4-6, ap. 2-3; lat. frust. 4-6 /x. 



Lismore (1, 12, 13, 17, 18, 21). In profusion. 



