2 Brannon. — The Structure and Development of 



Norfolk, New Jersey, and appears abundantly in Long 

 Island and Vineyard Sounds. The writer has also collected 

 fine specimens at Nantucket. Possessed of brilliant lake-red 

 colour and delicate texture, it constitutes a notable specimen 

 in every representative collection of the New England 

 marine flora. 



History. 



The elder Agardh placed this Alga in the genus Delesseria, 

 which 'then comprehended almost every Alga with a red 

 membranaceous leaf-like frond, and also included within its 

 limits Plocainium and Stenogramme.' It was referred later 

 to Nitophyllum, but was found to differ radically in the form 

 of conceptacle, shape of frond, and position of midrib. For 

 a time it seemed that it was to have fellowship with Hemineura, 

 but the different position of conceptacle, lack of similarity in 

 nervation and ramification, gave sufficient distinction to deny 

 admission to this genus. 



After a somewhat careful study of the plant. Dr. Harvey 

 raised it to the rank of an independent genus. He named it 

 Grinnellia, as a memorial to the 'noble conduct of Henry 

 Grinnell of New York, chief promoter of the search after the 

 missing Arctic expedition of Sir John Franklin.' 



General Morphology. 



In his description of Grinnellia, Harvey says that this Alga 

 has a frond which is ' rosy-red, leaf-like, delicately membra- 

 naceous, areolated, symmetrical, traversed by a slender per- 

 current midrib. Conceptacles scattered over the surface of 

 the membrane, bottle-shaped, with a prominent orifice ; 

 placenta basal, somewhat prominent, crowned with a pul- 

 vinate tuft of subdichotomous spore-threads whose terminal 

 cells are earliest ripened. Spores elliptic oblong or roundish. 

 Tetraspores tripartite, immersed in scattered shapeless cellular 

 warts.' 



In addition to these statements regarding the gross anatomy 



