98 PROCEEDINGS OF THE AMERICAN ACADEMY. 



growth of cortical cells. It is to be regretted that more is not known as 

 to the mode of growth of the frond. As it is, this alga, although at first 

 sight it suggested Peyssonnelia ntgosa Harv. in its habit, cannot be re- 

 ferred to that genus, for the frond in section is seen to be symmetrical 

 except that the cortical cells on the under side are more uniformly in a 

 single layer than above, but quite different from the well-defined base of 

 Peyssonnelia. Nor can it be considered a prostrate form of Kallymenia 

 or Constantinea, to which it appears to be more nearly related. It might 

 be suggested that the specimens were abnormal developments of some 

 species with erect fronds, but the abundance of sporidia appear to indi- 

 cate that the growth was normal. 



Hypnea, Lamx. 



H. pannosa, J. Ag. Oefv. Kongl. Vet. Akad. Forh. iv. 14 (1847). 



— Albemarle Isl. : Tagus Cove, Feb. 1889, Snodgrass & Heller. 

 Further distrib. tropical seas. 



Laurencia, Lamx. 



L. obtusa (Huds.) Lamx., var. gracilis, Harv. Ceyl. Alg. 26 ; 

 Piccone (1), 80. — Chatham Isl. : March, 1884, Marcacci, ace. to 

 Piccone, I.e. Further distrib. general. 



LlTHOPHTLLUM, Phil. 



*L. Farlowit, Heydrich in Engler, Bot. Jahrb. xxviii. 532, t. 1, f. 6 

 (1901). — Charles Isl. : Hassler Exped. Endemic. 



LlTHOTHAMNIUM, Phil. 



L. crassum, Phil. Weigm. Arch. 1837, 2, p. 388 ; Piccone (2), 45. 



— Charles Isl. : Marcacci, ace. to Piccone, 1. c. 



No specimens of this species have been seen, and I am unable to say 

 whether the alga collected by Marcacci on the Pisani Exp. is the same as 

 the L. crassum, originally described from the Mediterranean, as that 

 species is now understood. 



Melobesia, Lamx. 



M. corticiformis, Kiitz. Spec. Alg. 696(1849). — Wenman Isl. .- 

 on Gelidium serrulatum, Dec. 1888, Snodgrass & Heller. Further 

 distrib. general. 



M. pustulata, Lamx. Hist. Polyp. Flex. 315, t. 12, f. 2 (1816); 

 Piccone (1), 65. — Chatham Isl.: (on Zonaria lobata) Marcacci, 

 ace. to Piccone. 1. c. Further distrib. general. 



* Name changed to L. claudescens, Heydrich, Ber. deutsch. bot. Ges. xix, 430, 

 as it is antedated by L. Farlowii, Foster. 



