258 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Halodictjon mirabile Zan. Washed ashore, St. Ann's Bay, March 30, 

 1893, H. 



Spermothamnion Gorgoneum (Mont.) Bornet. On Codium tomento- 

 sum, Port Antonio, Aug., 1894; Kingston, July, 1900, P. & B. Port 

 Antonio, Feb. 27, 1893, No. 175 a, H. P. B.-A., No. 441. 



" Both cystocarps and polyspores have been found in Jamaica speci- 

 mens ; in the former the spores have thick cell walls and are arranged 

 as in Spermothamnion ; the involucre is only slightly developed. The 

 polyspores are quite numerous, in an ovate or subspherical mass, occu- 

 pying not more than half the diameter of the large, hyaline sporangium." 

 Note from label of P. B.-A., No. 441. 



S. Turneri var. variabile J. Ag. On Bryothamnion Seaforthii, Kings- 

 ton, July, 1900, P. & B. 



Callithamnion byssoideum var. Jamaicensis Collins. In dense 

 tufts on rocks, Port Antonio, Feb. 27, No. 170, H. P. B.-A., No. 443. 



" This plant has the divided cystocarps, with conical lobes, characteris- 

 tic of C. byssoideum ; antheridia and tetraspores also agree ; but the 

 habit is strikingly different, everything being condensed, the branches 

 relatively shorter and stouter, and very densely set, the terminal ramuli 

 often arranged more like C. corymbosum. It may possibly be the same 

 as C. Hypneae Crouan in Maze & Schramm, Algues de Guadeloupe ; 

 the name must be considered as provisional, awaiting comparison with 

 authentic specimens of the latter." Note from the label of P. B.-A., 

 No. 443. 



C. corymbosum (Eng. Bot.) Lyng. On Codium tomentosum, Port 

 Antonio, Aug., 1894, P. & B. 



Haloplegma Duperryi Mont. Washed ashore, Morant Bay, Annotto 

 Bay, Orange Bay, 1894; Kingston, July, 1900, P. & B. Only a few 

 fragments at each place. 



Crouania attenuata (Bonnem.) J. Ag. On Cryptonemia crenulata, 

 Morant Bay, July, 1894, P. & B. In small tufts, Navy Island, March 

 10, 1893, H. 



Antithamnion Butleriae n. sp. Fronds erect, ecorticate, simple or 

 with a few branches, which may be dichotomous, alternate, or occasion- 

 ally opposite, diameter near base about 30^, cells 3-6 diameters, walls 

 tliick. The lower portion of the frond or branch is naked ; above that 

 each cell bears normally a pair of ramuli, issuing at about two-thirds the 

 height of the cell ; the lowest ramuli are simple, subulate, of from two to 

 six cells about as long as broad; sometimes by the suppression of a 

 ramulus the branching is apparently alternate ; fiirther up the frond these 



