central cellules are of large size, in a single row in the lamina, and in several 

 rows in and about the midrib ; the intermediate and cortical cells are much 

 smaller, irregularly placed, and gradually become smaller to the surface. 

 The fruit-leaflets or sporophylln are very small, obovate, undulate, thin in 

 substance, and imperfectly ribbed ; they are found on the midribs of the 

 smaller leaves, and contain either cystocarps or a sorus of ietraspores. 

 The colour is a full dark-red or blood-colour, and becomes rather deeper in 

 drying. The frond very imperfectly adheres to paper in drying. 



The structure of the membrane in this species is different 

 from that in most others of the genus, with the exception of D. 

 Hookeri and perhaps D. Midclendorjli, to both which it seems 

 to be allied, though very distinct from either. If difference in 

 cellular structure be alone a sufficient ground for distinguishing 

 genera among the Algae, these three species might be separated 

 as a genus ; as it is, they form a natural section. 



An imperfect specimen of this plant, sent by Mr. Mylne from 

 Australia, and given to me by the late Dr. Lemann, is described 

 in Ner. Austr. p. 21, under Sarcomenia delesserioides, to which I 

 doubtfully referred it. The two plants have a very similar habit, 

 and not a very different structure ; but their fructification is 

 quite different : as may be seen by comparing the pod-Hke, tetra- 

 spore-bearing fruit of Sarcometiia (Plate CXXI.) with the broad 

 fruit-leaves of our present Plate. 



Fig. 1. Delesseria COEIIFOLIA, — the natural size. 2. /^orojo/ijy//ffl, containing 

 tetraspores. 3. Some tetraspores, 4. Semisection of the lamina in a small 

 leaf. 5. Section at the midrib, in the same ; the latter figures variously 

 magnified. 



