BY G. I. PLAYFAIR. 329 



Cos. THOLIFORME Cohn. 



Long. 100, lat. 75, isth. 42 /x. 



Lismore (185). 



Cf. Cohn, Desm. Bongoenses, p. 9, '1'. xi., f.9, semicell inferior. 

 This desmid belongs to a small group of Cosmai'ia which have 

 depressions in the membrane alternating with verrucse. In this 

 form, the markings on the membrane are arranged in vertical 

 and decussating lines. They are of two kinds; the larger, with 

 indistinct edges, appear to be depressions; the smaller, which 

 focus sharply, smooth verrucas. Cohn classes them all together 

 as conical papillae, but the markings on the upper semicell of his 

 figure seem to contradict this. The depressions are first trian- 

 gular, then irregularly hexagonal, finally circular. 



Genus E u a s t u u m Ehr. 

 Eu. siNuosuM var. campanulatum mihi. 

 Long. 100, lat. 55-57, ap. 20-21, isth. 12 /t. 

 Lismore (185, 240;. 



Syn., Eu. campanulatum Playf., Desm. N.8.W., p.l76, Pl.iii., 

 f.l6. 



Eu. TURGIDUM var. MoEBii(W. (fe G. S. West) Playf. 



Long. 114, lat. 95, lob. apic. 74, isth. 32 jx. 



Lismore (185, 250). 



Syn., Micr. Mobii W. k G. 8. West, Desm. Singapore, p. 162. 

 The figures of Eu. turgidum Wallich, Desm. Bengal, T.14, f.l7, 

 18, show that the type has a simple apical lobe (not bifid at each 

 side as in var. Mobii), Wallich's side-view agrees exactly 

 with mine (for var. Auburnens^i Playf.) in Some Sydney Desm., 

 PI. xii., f.2. In forms with bifid apical lobes, the apex, in side- 

 view, is much broader. 



Genus Micrasterias, Ag. 



MiCKASTERIAS TROPICA Nord. 



Long. max. 125, centr. 114; lat. max, 100, lob. pol. 44, coll. 20, 

 isth. 18; crass. 33 /x. 

 Lismore (185). 



