MAKINK ALO/K "1 I III -i ,.| M>II NATIONAL ANTARCIh 1: \ PI hlTloN. 75 



the Clml Ir i. 'j- > l"rm the same locality, ami prrsrr\.-d in tin- herbaria of the Brilinh 

 -mn ami the Royal (ianlons, Kr\v. 



10. ' .YMNini:i ^ \.\r.in.\n-, / I' Two spcrimriis without fruit. Off Brazil, 

 same locality as No. 3. 



j'liifil Ih.-itriliiitixn. Warm Atlantn-, Warm I'a.-itir, \\> .1 Sra. 



11. Sr\ r-'i'Dhii'M I.IIIUMM. Kiitz. Five s| ..... iinen.H without fruit. Off Brazil, Hame 

 locality as No. 3. 



Geographical Distribution. Canaries, Wait Indies, Chatham Island. 



12. DICTYOTA DICHOTOMA, Lam. Off Brazil, same locality as No. 3. 



These plants show a variation from the ordinary type, inasmuch as the two branches 

 of the final dichotomy take on the narrow form characteristic of f. intricata. 

 Below this final dichotomy the plants are quite typical, and the change is a 

 suiKlen one. Mr Lloyd Williams has been so kind as to give us his opinion ou 

 our of tin- specimens, saying that this development is probably the result of 

 unfavourable environment at a late stage of growth. He adds that he is able to 

 bring about such a change artificially in laboratory cultures. It is recorded as 

 having been taken at a depth of 36 fathoms a very deep habitat for a Dictyotn. 

 But possibly it was caught Moating free in the water ; and possibly it is a sturvation- 

 form. When an alga is fixed, it thrives in the food-bearing currents which sweep 

 past it ; but if it should break off and Boat away in such a current, it would soon 

 exhaust the food in its neighbourhood, and would then be in risk of starvation. And 

 if carried down to an undue depth, it would pass out of the zone of optimum conditions 



of light, CO,, etc. 

 V 



13. PHYLLOOIOAS SIMULANS, comb. nov. 



Syn. Lessonia grandifolia, A. and E. S. Gepp pro parte in Journ. of Hot,, xliii., 1905, 

 p. 105, tab. 470, fig. 6. Lessonia simulans, A. and E. S. Gepp in Journ. oj Hot., 

 xliv., 190*. p. 425 ; National Antarctic Expedition, iii., British Museum (Natural 

 History), 1907, "Marine Algae," pp. 5-7, pi. ii., fig. 10. Phyllogigas grandifolia, 

 Skottsberg pro parte in Wissen. Ergebn. Schwed. Siidpolar-Exp., Bd. iv., Lief. 6, 1907, 

 pp. 63-69. 



I'laiita incompleta. Frons laminarioidea ut in P. grandifolia, stipite complanato 

 nm-ipite suffulta, simplex, lanceolato-linearis, longa, lata (12'5 cm. plusve), marginibus 

 integerrimis. Laminae substantia pergamentacea vel coriacea, e stratis tribus composita ; 

 cellulis corticalibus monostromaticis quadratis granuloso-obscuris ; subcorticalibus 

 oblongis parcnchymaticis in circa 6-7 series dispositis ; medullaribus congestis elongatis 

 angustis strictis 9-10-seriatis tubulos perpaucos subinfundibuliformes vagina e cellulis 

 parvulis composita vestitos foventibus. Caetera desunt. (Fig*. 6, 7.) 



Habitat. Scotia Bay, South Orkneys, near surface, April 1U04, It. A r . Rudmose 



