16 52 Proceedings of the Royal Irish Academy. 



Navicula Lyra Ehrenb. — CB, 124^ long; AS, llo^u long ; C. 



f. MINOR, forma nova, — F. cellulis fcypicis in forma, sed multe 

 minoribus, 64 x 28"2^. Cn. 

 musca Greg — C, 46 x 16 - 5/z ; AS, 46 x 19ju, istbmus 152/i. 



var. PARVA, var. nov.— Var. cellulis multe parvioribus. CB, 

 33 x 14*2^; AS, 35 x 13"8/i, isthmus 91/.<. 

 mutica Kiitz. — C, very variable; M. 



palpebralis Breb. — AS; L, at mouth of Bunowen river, 56 x cOfi, valve- view. 

 Smithii Breb. — C, a small form 54x25^; AS, also small forms; ONE. 

 var. MINOR, var. nov. — Var. cellulis semper minoribus, 46 x 26^. 

 C. 

 trevelyana Donk. — K, 131 x 36/n girdle-view. 



var. MINOR, var. nov. — Var. cellulis brevioribus et relative 

 latioribus in visa cinctuare. AS, 60,u long, 20ju at widest 

 part of girdle-face ; a relatively shorter form. 

 **vacillans Ad. Schni. — CNE, 25 x 10^, constriction slight. 

 "Berkeleya Dillwynii (Ag.) V.H. — CNE, 38 x 6,u. 

 Scoliopleura latestriata (Breb.) Grim. — AS, 100x20^. 



Tribe Gomphonemeae. 

 Rhoicosphenia curvata (Kiitz.) Grun. var. marina (\V. Sm.) V. H. — C, L. 



Tribe Achnantheae. 



Achnanthes Bubsessilis Ehrenb. — C, OB ; M, 36 x l2/i, valve-view. 



brevipes Ag.— C ; M, 56 x 12-5/i, a small form; L, 58 x 15'8,u ; CNE, 



56-63ju long, 

 'delicatula Kiitz. — C ; M, 18-22 x 10^, valve-view, 

 longipes Ag. — C, CB. 



parvula Kiitz. — AS, 13'3 x 8 - 3;u, some specimens occurred up to 21/j. 

 long; C. 



Tribe Coeconeideae. 

 **Cocconeis danica Plug. — CB. 



Mirupta Greg— CB, 31 x 242^ ; CNE, 29 x 23 /( , 25 x 21^, 18 x 13^, 



28 x 21 M ; K. 

 molesta Kiitz.— C, 17^ long ; CNE, 18-20/* long, also up to 28 x 20/*, a 



large form. 

 pinnata Greg. — C, CB. 

 Scutellum Ehrenb.— C, AS ; BE, extremely abundant; CNE, K. 



f. parva V. H.— AS ; CNE, from 10 to 6/* up to 25 x IS/* ; M, K. 



