No. 5] NEW OR CRITICAL CALCAREOUS ALGÆ. 15 



of the plants described by Johns ton, Brit. Spong, and Lith., and 

 Harvey, Phyc. Brit. is no doubt according to specimens in Sci- 

 ence and Art MLiseum's herbarium, Dublin, and in other herbaria. 

 However, the woodcut by Johns ton 1. c. gives a better idea of 

 the plant in question than the picture b^^ Harvey 1. c. There 

 seems perhaps to have been some mistake as regards the latter 

 which partly resembles f. agariiformis partly reminds of Litlio- 

 pJiyllum dentatum f. Macallana. However, the description by 

 Harvey refers to f. agariciformis in the sense here tåken, except 

 that it is quoted to be hollow which scarcely applies to the latter 

 but on the contrary to the said f. Macallana. 



Among the specimens of f. agariciformis that I have seen the 

 largest is about 16 by 11 cm. in diameter and about 4 cm. thick, 

 but I am not quite sure whether they have in fact been tåken at 

 Roundstone, nor by whom coUected, though probably either M'Calla 

 or Dr. F ar r an. The plant is also said to have been collected at 

 Roundstone by Dr. Robert son. The specimens are at any rate 

 from the west coast of Ireland, but all of them unfortunately being 

 sterile. At present I do not, however, hesitate to ascertain it a 

 form of L. lichenoides. Cp. Harvey's remarks under the latter 

 species in Phyc. Brit. pl. 346, and Manual, ed. 2, p. 109. It fully 

 agrees in structure especially with f, depressa. As mentioned in 

 A visit to Roundstone in April-) Mr. Hanna and I did not suc- 

 ceed in tinding t^-pical specimens of it, though in the lower part 

 of the litoral region transitions were found. And from the Isle of 

 Man I have seen small specimens which almost fully coincide with 

 the said specimens in Science and Art Museum. They are fur- 

 nished with typical conceptacles of sporangia. 



The said form is quoted by Harvey 1. c. to be found „lying 

 on the sandy bottom of quiet bays, in 2 — 3 fathoms water". 

 John st on refers 1. c. p. 241: „Dr. Farran of Feltrim near 

 Dublin informs me that it is found on a small bank in water about 

 fifteen feet deep, and appears like paving stones at the bottom: 

 the only locality he knovi^s is Roundstone bay, Connamara, where 

 he observed it seven or eight years ago (Wm. Thompson)". I 

 1) The Irish Naturalist. Vol. VIII. 1S99. Pag. 175. 



