92 SPH^ROCOCCOIDE^. v. 



our plant has also been referred, but, besides the form of the conceptacle, Grinnellia 

 differs from Nitophyllum in having a perfectly symmetrical frond, furnished with 

 a single percuri^ent midrib. In some examples this midi'ib is very slender, but I 

 believe it may always be distinctly traced, at least in the living plant ; and when 

 the frond is bifid, as it occasionally is, the midrib regularly bifurcates, one arm pur- 

 suino; each branch. A farther characteristic, showing the difference between this 

 midi'ib and the irregular veins of Nitophyllum, is that in Grinnellia the midribs of 

 old fronds become gradually stripped and converted into stems, and are then 

 often proliferous ; perfectly formed, ribbed leaflets springing from them. The only 

 other genus of which it is necessary to speak is Hemineura (Harv. Ner. Austr. t. 45) 

 but the different nervation and ramification, as well as the position of the concep- 

 tacles, afford sufficiently obvious distinctions. 



The generic name, Grinnellia, is bestowed in honour of Henry Grinnell, Esq. 

 of New York, whose noble conduct in promoting the search after the missing Arctic 

 Expedition of Sir John Frankxin justly entitles him to the respect and gratitude 

 of every man of science. Doubtless there will be other and more worthy memo- 

 rials ; but yet it seems to me that a beautiful marine plant may not unfitly preserve, 

 among the Algologists of America and England, a kindly remembrance of an act 

 of disinterested kindness to wanderers at sea, or let me rather say, a naval action 

 to which both Nations may look back with undivided feelings. 



1. Grinnellia Americana. — Delesseria Americana, Ag. Sp. Alg. 1, p. 173. /. 

 A(j. Sp). Ahj. 2,^*. 681. Aglaiophyllum Arnericdnum^-Mont. in An. Sc. Nat. 3c?. Ser. 

 vol. xi.p. 63. Cryptopleura Americana, Kiitz. Sp. Alg. p. 872. (Tab. XXI. B.) 



Hab. On stones and shells, in four or five fathoms. Abundant in Long Island 

 Sound and New York Harbour, (v. v.) 



Boot scutate. Frond densely tufted, leaf-like, from one to two feet in length, 

 and from one to four inches in width at the widest part, lanceolate, tapering to the 

 base, and usually also to the apex, but sometimes very obtuse and sometimes bifid, 

 delicately membranaceous, waved and often curled at the margin, traversed by a 

 slender, slightly wavy, central nerve, which runs through the frond from the base 

 to the apex, gradually becoming more slender upwards, being as thick as hog'a 

 bristle in the lower part of the leaf and as fine as human hair towards the tip. 

 The frond usually consists of a single leaf, or of three or four leaves springing a 

 short way above the base of a common stem ; but when the membrane of the leaf 

 is destroyed by the waves, as often occurs, the old midrib survives and throws out 

 numerous leaflets, and the frond becomes compound. Such secondary leaflets are 

 usually small and densely crowded. Fructification of both kinds abundantly pro- 

 duced and scattered thickly over both surfaces of the membrane. Conceptacles 

 resembling in form ancient lacrymatories or the wide glass jai-s in wliich sulphuric 

 acid is commonly sold, depressed hemispherical, with a more or less prominent ori- 

 fice, the neck varying in length on the same plant in different conceptacles. The 



