F. Børgesen: Rhodophyceæ of the Danish W. Indies. 



239 



branchlets and ramuli. By this and also by the very regular 

 alternating of the branchlets the plant has often a fine, feathery 

 appearance. To judge from J. Agardh's description of Spyridia 

 complanata this plant seems to be very like the present form, 

 but, while my plant has a terete thallus, Agardh's plant is said 

 to be compressed. On account of this I prefer to consider my 

 plant as a form of Sp. aculeata. 



Of this form 1 have had specimens from both shallow and 

 deep water (about 30 meters). The specimens from shallow water 

 are very robust and densely ramified ; the ramuli are short and 

 thick, composed of nearly quadratic cells which, in the lower 

 part, are about 1^ p. long and broad. Uncinate spines are deve- 

 loped, not only from the uppermost cortical ring in the ramuli, 

 but sometimes, too, from the next one. 



Compared with these specimens the ones from deep water 

 are much more slender in all respects. The ramuli are of more 

 than double the length, 

 their cells slender and 

 much longer, about 

 50— 60/i broad, 130 ;^ 

 long. The specimens 

 have a beautiful, fea- 

 thery appearance. 



f. inermis n. f. 



A var. disticha 

 præcipue differt aculeis 

 uncinatis rarissimis aut 

 nullis. 



Fig. 229. Spyridia aculeata (Schimp.) Kütz. 



var. disticha n. v. Part of a plant and the 



upper end of a ramulus. (About 18 : 1 and 



200 : 1). 



This form is cha- 

 racterized by the ab- 

 sence of the uncinate 



spines upon the ramuli. On account of this fact I was at first inclined 

 to consider it as a new species, but after a more thorough in- 

 vestigation, having examined several parts of different specimens, 

 I have twice come across a ramulus bearing a single uncinate 

 spine, and I therefore prefer to consider it as a non-aculeate form 

 of the present species to which it otherwise shows very great 

 likeness. 



The specimens found reach a height of more than 20 cm. 



