nearly linear. Both forms occur together, and sometimes on the same 

 specimen. Cystocarps generally occur on the narrower varieties, and mostly 

 on the margins of the smaller pinnules. A.gardh describes the son" of 

 tetraspores as being linear and marginal. The colour is a deep vinous 

 red-brown. The substance is firm, cartilaginous, horny when dry ; and the 

 plant does not adhere to paper. 



In the genus Gigartina, as now understood, are retained a 

 considerable number of species, dispersed over most parts of 

 the world, from the tropics to high northern and southern lati- 

 tudes ; differing very much in external habit, but all agreeing in 

 structure and fructification, and in the hvid- or brownish-purple 

 colour of the frond. Some (hke G. radula), have broad, simple 

 leaves, resembhng those of an Iridaa ; others have flabelliform 

 fronds like those of a Chondrus or Gymnogongrus ; others are 

 shrubby and irregularly branched, like a Gracilaria ; and others, 

 again, in the regularly pinnated and distichous ramification, Hke 

 our G. pimiata, remind us of the Laurencice. The present is 

 one of the finest of the Australian kinds, and would require a 

 folio plate to do it full justice. It varies considerably, and I 

 shall not be surprised if future observations, made on the shores 

 of Australia, should compel the union of G. livida and some 

 others with it. 



Fig. 1. GiGARTiNA PiNNATA, a branch, — of the natural size. 3. Fertile branchlet 

 of a larger frond, — natural size. 3. A ramulus, with conceptacle. 4. 

 Section through conceptacle, showing structure of frond and favellidium. 

 5. Spores. 6. Portion of the cortical layer and medullary network, — the 

 latter figures variously magnified. 



