118 INTRODUCTION TO CRYFTOGAMIC BOTANY. 



have chosen for illustration, is one detected on the chalk cliffs 

 of Norfolk, by Sir W. J. Hooker, and, perhaps, the group is 

 incapable of any higher development. Other forms depend 

 upon the comparative compactness of the gelatinous mass in 

 which the reproductive bodies are contained, and on the 

 cellular structure assumed by some, as in Botrydhia, from the 

 close pressure of the several component cysts. 



96. The next group is that of Pahnella. If the figures of 

 Kiitzing,* relative to this group, be examined, there will 

 be seen in many, an evident trace of slender, supporting 

 threads. Mr. Thwaites,-(- however, seems to have been the 

 first who properly described this structure, and it is prol)able 



// 



Fig. 29. 



Pcdmella hotryoides, Greville. 



A portion of the threads which radiate from a large central cell, 

 forked at their tips, and supporting on them elliptic cells, surrounded 

 with gelatine, highly magnified. From a specimen communicated by 

 Mr. Thwaites. Compare Nageli Gattungen Einzelliger Algen, tab. 2. E. 



that it belongs to the greater part of the species, | and that 

 some which do not really possess it, would be better associated 

 with the group first mentioned (95). There seems in these to be 

 rarely any such multifold division of the endochrome, or adhe- 

 rence after division, as often prevails there. The spores them- 



* Tab. Phycologicse, tab. 19, iv. 21 ; v. 25; i. and v. 26 ; i. and ii. 



f Ann. of Nat. Hist., vol. xi. p. 312. 



X A figure of a new species of Coccocliloris, C. Brehissonii, Thw., is 

 given in Ann. of Nat. Hist., March and April, 1849. This possesses 

 the same filamentous supporters as P. botryoides. The structure of the 

 frond of Synalissa and Paulia, two gelatinous Lichens, exactly accords 

 with that of Coocochloris, 



