io 4 ANNALS OF SCOTTISH NATURAL HISTORY 



f. subverticillata, " Kiitz. Tab. Phyc." 



5, t. 77, fig. n. 

 f. rupincola, " Kiitz. Tab. Phyc." 5, t. 



76, fig. 1. 

 f. rectangularis. 



Sub-species /3, firmus, Kuck. 



f. typica, " Wyatt, Alg. Danm." No. 1 29. 



f. subglomerata. 



f. livida. 



f. pacliycarpa. 



Sub-species 7, divaricatus, Kuck. 



f. ramellosa " Kutz. Tab. Phyc/' 5, t. 78. 



Sub-species S, varius, Kuck. 



f. typica, " Kjellm. Alg. Arct. Sea," t. 



27. figs 1-12. 

 f. contorta. 

 f. pumila. 



Kjellman, on the other hand, divides P. litoralis into 

 three varieties and several forms, as follows : 



Var a, opposita, Kjellm. 



f. rupincola, "Aresch Alg. Scand. Exs.," 



No. 1 13. 

 f. elongata. 

 f. crassiuscula. 

 f. nebulosa. 



Var. /3, firma, J. Ag. 



f. olivacea, Kjellm. 



f. macrocarpa, Fosl. " Nye Hafsalg." 



5, t. 2, figs. 13-15- 

 f. parvida, Kjellm. 



Var. 7, divaricata, Kjellm. 



f. prcetorta, Kjellm. 

 f. azgagropila, Kjellm. 

 f. sub salsa, Kjellm. 



None of these, except f. rupincola, are identified by 

 Kuckuck with the forms described by him. 



The limit of a species doubtless forms a very vexed 



