THE NATURAL HISTORY OF AILSA CRAIG. 



151 



some affinity with that of the Mourne mountains, is there any 

 similarity in the flora of the two districts ? I do not know — I 

 merely throw out the suggestion. The ice of the glacial period 

 would swathe all these areas ; it cannot be invoked in this case of 

 difficulty as a deus ex viachind. When milder conditions again 

 prevailed what influence scattered Arctostaphylos on the Holy 

 Isle and left Ailsa poor and bare ? 



Diatomackte. — Mr. John Paterson (Rutherglen) made a col- 

 lection of Diatoms on our last visit (24th May, 1900), and with 

 the much valued assistance of Mr. Thomas Comber, F.L.S., the 

 following thirty-eight species and six varieties have been made 

 out and named. 



Cymbella affinis, Ktz. 

 C. cistula, Van Heurck. 

 Caloneis fasciata, CI. 

 Diploneis ovalis, CI. 

 Navicula lanceolata, Ktz. 

 Pinnularia subcapitata, Greg. 

 P. borealis, Ehr, 

 P. borealis, var. scalaris, Grun. 

 P. gracillima, Greg. 

 P. hemiptera, Breb. 

 P. interrupla, Sm. 

 P. lata, Sm. 

 P. major, Rabh. 

 P. viridis, Ehr. 

 P. viridis, var. fallax, Grun. 

 Gomphonema montanum, Schum 

 var. subclavatum, Grun. 



Fresh-water. 



Microneis minutissima, CI. 

 Epithemia turgida, Ktz. 

 E. zebra, Ktz. 

 Eunotia exigua, Grun. 

 E. gracilis, Sm. 



Synedra lunaris, Ehr. (short form). 

 S. lunaris, var. subarcuata, Nag. 

 Fragilaria virescens, Ralfs. 

 Odontidum hiemale, Ktz. 

 Denticula inflata, Sm. 

 Tabellaria flocculosa, Ktz. 

 Surirella splendida, Ehr., var. 



linearis, Sm. 

 Nitzschia denticula, Grun. 

 N. sinuata, Grun. 

 Melosira Dickiei, Ktz. 



Cyclotella Kutzingiana, Thw. 



The above were all obtained in pools and ditches. The most 

 uncommon of them, viz., Pinnularia borealis, var. scalaris, was also 

 obtained as a pure gathering from a moist crevice in the cliffs. 



Marine. 



Trachyneis aspera, CL, var. 



pulchella, Sm. 

 Caloneis amphisba;na, CI. 

 Rhoicosphenia curvata, Grun. 

 Cocconeis scutellum, Ehr. 

 Eucocconeis pseudomarginata, CI. 

 Synedra Gaillonii, Ehr. 



Grammatophora marina, Ktz. 

 G. serpentina, Ehr. 

 Rhabdonema Adriaticum, Ktz. 

 R. arcuatum, Ktz. 

 Cyclotella striata, Grun. 

 Coscinodiscus decipiens, Grun. 



