126 SUPPLEMENT. 



shows a central axial-cell surrounded by several primary radiating cells, and many 

 external rows of secondary cells which become smaller towards the circumference. 

 Colour a dull brownish red. Substance cartilaginous, not adhering to paper. 



I have seen but a single specimen of this seemingly very distinct plant, which has 

 more the habit of Champia lumbricalis than of one of the present genus. It was picked 

 up, it is presumed on the Western coast, by Dr. Schott, during the Mexican Boundary 

 Survey, but no note regarding its exact habitat accompanied the specimen. I am 

 indebted to my friend Professor Torrey for specimens of this and other Algae collected 

 by the officers attached to the Mexican Boundary Survey. 



Plate L. B. — Fig. 1. Chondru nidijica ; the natural size. Fig. 2. Portion of a 

 branch, with a tuft of ramuli. Fig. 3, a ramulus, containing tetraspores. Fig. 4, a tetra- 

 spore. Fig. 5, transverse section of a branch ; the latter figures more or less magnified. 



Page 36, add, 



4.* Rhodomela lycopodioides, Ag. ; frond divided near the base into several long, 

 simple branches, which are densely beset with slender, finely divided branchlets, mixed 

 with the short, rigid, bristlelike remains of a former series. Ag. Sp. Alg. 1. p. 877- 

 Harv. Phyc. Brit. t. 50. Lophura lycopodioides^ Kiitz. Sp. Alg. p. 850. Ficcus lyco- 

 podioides, Linn. Turn. Hist. t. 12. E. Bot. t. 1163. 



Hab. Whalefish Islands, Davis Straits, Dr. Lyall. (v. s.) 



Fronds 1-2 feet long, half a line in diameter at base, attenuated upwards, filiform, 

 either quite simple or divided a short way above the root into several long simple 

 branches. In its winter state the virgate branches are closely set with short, rigid, 

 simple or slight divided ramuli, from half an inch to one inch in length. In summer, long, 

 capillary, multifid ramuli from one to two inches in length are thrown out both from 

 the remains of the winter ramuli and from the main branches, and the frond thus 

 acquires a plumose aspect very difierent from its winter state. Conceptacles are abun- 

 dantly borne on the summer ramuli ; and tetraspores., lodged in clustered, podlike 

 branchlets or stichidia, are found on the winter ramuli. Substance cartilaginous. 

 Colour a purplish brown, becoming very dark in drying. 



This interesting addition to the American Nereis occurs abundantly in various places 

 on the shores of Northern Europe. In the British Isles it is almost confined to the 

 coasts of Scotland and of the North of Ireland ; but has occassonally been met with on 

 the East coast of England. 



Page 69, 



1. Dasya GiBBEsn, Harv. 



Add to the description : Conceptacles of large size (^ inch in diameter), borne on 

 the penultimate ramuli, at first globose, afterwards broadly ovate, inflated, with thin, 

 highly cellular walls and a berry-like nucleus of much branched filaments, bearing many 



