(102) 



inches in length, scarcely one-fourth of a line in diameter at the base, 

 and from one line to half an inch in diameter at the widest part, the 

 apex generally acute, surface smooth when yoimg, rough when old, 

 frequently constricted, inflated, or contorted. Fructification : minute 

 roundish spores, nestling among short, cylindrical, articulated filaments, 

 collected into small roundish spots or sori, and scattered over the 

 whole surface of the frond. Structure consisting of rather large 

 roundish cells mixed with smaller ones, forming a more or less cylin- 

 drical tube, with rather thick walls. Substance soft and flaccid when 

 young, and closely adhering to paper ; when old, hard and not adhering. 

 Colour, when young, a greenish olive brown ] when old, entirely brown. 



This is an exceedingly common species, frequenting shallow stony 

 pools between tides, often near high- water mark, where the small con- 

 torted form may often be observed mixed in the same tuft with the 

 larger and more luxuriant state. When young, it is not by any means 

 an unhandsome plant ; but as it advances in age it often becomes 

 covered with mud and innumerable minute parasites, which give it a 

 very coarse and unsightly appearance. 



From the last species it may be readily distinguished by its thicker 

 and less delicate substance, attenuated extremities, and more regularly 

 tufted habit. From E. compressus it is best known by the more obtuse 

 extremities and compressed frond of that species, and its more evident 

 reticidations. 



From Chorda lomentaria, when young, it is often no easy matter to dis- 

 tinguish it. In maturity, the vertical filaments of the periphery, and 

 the smooth surface, as well as the more regular and more numerous 

 constrictions, are pretty conspicuous characters in that species. 



We have also seen it confounded with Dumontia filiformis, but that 

 species is always more or less branched, of a very different colour and 

 substance, and very smooth surface. 



EXPLANATION OF PLATE CLXVL 



Fig. 1. — Asperococcus echinatus, natural size. 

 2. — Base of stem. 

 3. — Portion of stem. 

 4. — Section of frond with spores. 

 5. — Surface cells of same. All magnified. 



