16 32 Proceedings of the Royal Irish Academy. 



Navicula major Kiitz.— "W, M, IT, D, CI, L, SL; 0, 171 x 26/x (girdle-view). 

 In one gathering S. of Dugort, a small form occurred averaging 

 135 x 24^, girdle-view. 

 mesolepta Ehrenb.— C; M, 56 x lift; IT, L, W ; D, 58'5 x 12-5/«. 



var. Termes (Ehrenb.) V. H. — C, 47 x 9/a valve-view ; Cr ; D, 



27 x 6/u, valve-view, up to 47 x 11'6/x ; L. 

 var. PROTENSA var. nov. — Var. eellulis multe angustioribus 

 quarn in forma typica, lateribus regulariter triundulatis, 

 average size 63 x 8'8/x. W. 

 **minima Grun. — B. 

 nobilis (Ehrenb.) Kiitz.-W, 330 x 53/*; C, L, CI, D; M, 278 x 49^ 

 (valve-view), others 225 x 60/i (girdle- view). 



var. Dactylus (Ehrenb.) (V. H.)— C, 200 x 34/1, valve- view ; M, 

 one form was relatively narrow, 260/t long, 35/t wide, 

 another 184 x 22'7/x. 

 oblonga Kiitz. — L. 

 peregrina Kiitz.— C, L, SL, W, D, VL. 



var. PROD TTCTA var. nov. — Var. polis distincte productis, eellulis 

 latioribus quam in forma typica. Formae majores 118-119 x 

 37'5//, formae minores 71 x 29/*. C. (PI. II, fig. 22.) 

 Pupula Kiitz. — D, 30 x 9/a, among Hippuris vulgaris. 

 pusilla W. Sm. — D, in fresh water 200 yards from the sea ; C, a narrow 

 form in fresh water 39 - 5 x 15 - 4/t ; W, 29 x 13-3/i. 



var. PTJSILLISSIMA var .nov. — Var. eellulis multe parvioribus, 

 21 x 12%. D. 

 radiosa Kiitz. — C, 55 x 10/j ; K ; L, a narrow form, average size 70 x 9 p 5- 

 10,u ; IT, I, VL, CI, M ; W, 60 x 116^ ; D, LG. 



var. acuta W. Sm.— C, 92 x 12 - 5/<, 83 x 9 3/x, valve-view; 

 L, D, W, Cr. 

 Rabenhorstii Ralfs. — W. 



rhyncocephala Kiitz. — C, M, L; D, 51 x lOS/i; SL; W, a narrow form 

 48 x 10/*, as well as typical forms. 



var. amphiceros V. H. — D, 44 x 13"3. 

 f. robusta Eabenh. — W. 

 **8eminulum Grun. — C. 

 serians (Breb.) Kiitz. -C, SL, L, CI, W, SL. 

 var. brachysira (Br£b.) V. H. — M. 

 var. thermalis Grun. — B. 

 sphaerophora Kiitz. — C, 60 x 20/*. 

 *sublinearis Grun. — M, I. 



