COLLINS. THE ALGAE OP JAMAICA. 259 



ramuli are compounded with similar smaller subulate ramelli, appearing 

 first on the lower side of the ramulus. The upper pinnae have from 

 each cell of the rachis a pair of ramelli which touch each other laterally, 

 so that the pinna forms a continuous triangle. At the ti[)s of the 

 branches the cells are much shorter than those below, and the triangular 

 compound pinnae are in contact, giving a linear outline to the whole. 

 Color a rich rose. On Bryothamnion Seaforthii, Kingston, July, 1000, 

 P. & B. 



From A. pteroton (Schousb.) Bornet it differs in the more densely 

 branched pinnae, with ramelli on both sides, or on the lower only. From 

 Ptilothamnion micropterum (Mont.) Bornet it differs by the absence of 

 the apparent bifurcation of the pinua. Callithamnion microptilum Gru- 

 now has much shorter articulations in the main branches, and less dense 

 pinnules, which also are alternately more and less developed, as in some 

 species of Ptilota. In the absence of fruit it is impossible to determine 

 that the plant in question may not, when fruit is found, have to rather 

 bear the name of Ptilothamnion Butleriae. 



Spyridia aculeata Kuetz. Washed ashore, St. Ann's Bay, March 30, 

 1893, No. 337; in tufts, Port Antonio, March 10, 1893, No. 228, H. 



S. filamentosa (Wulf.) Harv. In dense tufts, Port Antonio, March 

 10, 1893, No. 222, H. Port Morant, Kingston, Montego Bay, Man- 

 chioneal, P. & B. Probably common everywhere. Chitty. 



Ceramium byssoideum Harv. Washed ashore, Port Antonio, July, 

 1891, P. & B. 



C. clavulatum Ag. Port Maria, Nos. 275 and 301 ; Port Antonio, 

 No. 183, H. Morant Bay, Manchioneal, Kingston, Montego Bay, P. & 

 B. Common everywhere and very variable. 



C. fastigiatum Harv. Washed ashore, Port Antonio, July, 1891 ; Ora 

 Cabessa, Rio Bono, Rio Novo, June, 1900. 



C. gracillimum Harv. On rocks, Apostles Battery, Kingston Harbor, 

 Apr. 10, 1893. H. 



C. nitens (Ag.) J. Ag. Washed ashore, Port Antonio, July, 1891 ; 

 INIanchioneal, Montego Bay, 1900, P. & B. 



C. tenuissimum (Lyng.) J. Ag. On eel-grass, St. Ann's Bay, March 

 24, 1893, No. 318, H. Port Antonio, July, 1891; Manchioneal, Mon- 

 tego Bay, 1900, P. & B. P. B.-A., No. 798. The Montego Bay speci- 

 mens are small, connecting the type with the following variety. 



C. tenuissimum var. pygraaeum (Kuetz.) Hauck. On Laurencia 

 obtusa, near Kingston, Duerden. P. B.-A., No. 896. A very small 

 form, hardly visible to the naked eye, but in full tetrasporic fruit. 



