166 CRYPTONEMIACE.E. v. 



Readily distinguished from the last geuus by the narrow, generally sub-terete 

 frond, never expanding into membranous leaves, and by the immersed concep- 

 tacular fruit. In external habit the Gymnogongri much more nearly resemble 

 species of Chondrus, in which genus several were formerly included, but they differ 

 from the true Chondri essentially in the structure of their medullary stratum. 

 Nearly twenty species are already known, natives of various parts of the world. 



1. Gymnogongrus Torregi, J. Ag. ; "frond compressed, flattish, dichotomous, 

 fastigiate ; the segments linear, very narrow ; the axils rounded." J. Ag. Sp. Alg. 

 2, jt>. 319- Sphcerococcus Torreyi, Ag. Sp. 2, p. 254. 



Hab. New York, Prof. Torrey in Herb. Agardh. 



'■'■ Fronds a s^&Tx long, regularly dichotomous, nearly terete below; segments linear, 

 veiy narrow, scarcely a line broad, gradually attenuated toward the obtuse apices. 

 Axils rounded ; all the segments ascending and forked at the summit. Substance 

 coriaceo-corneous, rigid. Colour^ in the dry state, brownish." Ag. 



I have not seen an authentic specimen of this plant, but have received from Mr. 

 Hooper a small fragment, which may possibly belong to it. It was found at Fort 

 Hamilton, and is about an inch high, and half a line in diameter, compressed, 

 flabelliform, fastigiate, dichotomous, the segments divaricating, obtuse, or sub- 

 truncate, sometimes emarginate. Colour a very dark red-brown. Substance carti- 

 lagineo-coriaceous. Structure as in the genus. This specimen resembles G. 

 Griffithsice, but is broader and more compressed, and the medullary cells are rather 

 different. It is well worth the attention of the Brooklyn Algologists to endeavour 

 to clear up the history of this little-known species. 



2. Gymnogongrus tenuis, J. Ag. ; " fronds tufted, flat, membranaceous, dichoto- 

 mous, sub-fastigiate ; segments linear, the upper ones narrower ; conceptacles 

 scattered, hemispherically prominent towards one surface of the lamina, flat towards 

 the opposite surface." J. Ag. Sp. Alg. 2, p. 319. 



Hab. On the shores of the Mexican Republic, Liebman, (v. s. in Herb. T. C. D.) 



Densely tufted, about an inch and half high, dichotomously-decompound, the 

 upper segments narrow or multifid. Axils sub-acute. Colour purplish. Substance 

 membranaceous, thin. 



Nearly related to G. Norvegicus but thinner in substance, of a purplish colour, 

 and with more prominent conceptacles. I am indebted to Senator Binder of Ham- 

 burgh for an authentic specimen. 



3. Gymnogongrus Norvegicus, J. Ag. ; frond linear, dichotomous, flat, fastigiate 



