PERFORATING BODIES FROM LOWER PALEOZOIC ROCKS — ETHERIDGE. 127 



NostoG carneum or N. commune* and again N. hyalimun.j It 

 would, perhaps, be out of place to call attention to the resemblance 

 between endophytic chains of cells of Palfeozoic age, with a genus 

 possessing a gelatinous thallus, or envelope, like JVostoc, were it 

 not for the fact that Mr. A. C. Seward has collected several in- 

 stances where the cells of Nostocaceaj in chains have been found 

 in calcareous pebbles at the bottom of lakes in Ireland, and in 

 the State of Michigan.^ The genera are Schizothrix, Nostoc, 

 Stigonema, and Dichothrix, the first-named enclosed in its com- 

 paratively hard tubular sheath. I have already stated that I 

 believed I could distinguish, in more than one instance, a sheath 

 or vagina, enclosing some of the moniliform chains. 



In the Nostochinepe, the trichome is either simple or branched ; 

 simple in the Nostocacete, branched in the Scytonemepe, etc. In 

 the present instance the trichome is decidedly branched, thus 

 showing a departure from the Nostocacea?. Furthermore, some 

 genera at least of the ISTostochinete contain marine species.§ As 

 to the endophytic habit, it is known that species of Nostoc occur 

 in the tissues, or mucilage-containing spaces of certain scale 

 mosses. 1 1 



In conclusion, and on the whole, it may perhaps be not too 

 much to say that there is evidence of the existence in Palasozoic 

 times of a iVostoc-like endophytic alga, which, for systematic pur- 

 poses, may be known as Palaiojjede^ ivhiteleggei. It is named in 

 honour of Mr. Thomas Whitelegge, of the Australian Museum, to 

 whom I am indebted for several valuable suggestions. 



* Cooke— Brit. Fresh Water Algse, 1882-4, Atlas, pi. xc, fig. 2, pi. 

 xci., fig. 5. 



t Bennett & Murray— Handb. Crypt. Bot., 1889, p 431, fig. 359. 



X Seward— Fossil Plants, i., 1898, p 123. 



§ Bennett & Murray— Handb. Crypt. Bot., 1889, p. 441 ; Seward — Joe. 

 cit., p. 122. 



1! Campbell— Mosses and Ferns, 1895, pp. 115, 117, 119, 122, etc. 



U TreBi], a chain or fetter. 



