-JO Cincinnati Society of Natural History. 



genus. There can not be the least doubt in the present case 

 that slrictus was the first species described under the new 

 generic name. This being the case, it is well to give the 

 description of the species. It is as follows : 



'■ FucoiDES STRiCTUS. — Frond linear, bifurcating, with 

 the branches erect, fastigiate and close together; midrib 

 broad, flattened, tuberculate and prominent, with undulate 

 margins. (PI. xix, Fig. 2.) 



" SphcBrococcus ? stricius Ag. MSS. 



" Rhodomela f dibiviana Ag. Spec. Alg. I, p. 383. 



'' Fucoides slricUis Ad. Br., Class, veg. foss., p. 37, tab. 3. 



fig- 3- 



" Locality. — In the lignite of the Isle of Aix, near La 



Rochelle. (Fleurian de Bellevue, d'Orbigny.) 



" This species resembles greatly in its general form Fuciis 



obtusatus Labill., N. Holl., but it diflFers in the large and flat 



nerve that traverses the frond, and that fails entirely in Fucus 



obtusatus. The fossil species has a more rigid and fastigiate 



aspect. The arrangement of the nerve shows some analogy to 



Fucus alatus, but it differs greatly by its size and more erect 



and scattered branches. The generic position in the Algae is 



very difficult to assign. It is probable that the tubercles 



observed on the middle nerve are the organs of fructification." 



Further remarks upon this and other .species of the genus 

 will be deferred until later on in this paper. 



In 1825 appeared volume one of a memoir by Sternberg, 

 under the title of " Versuch einer geognostisch-botanischen 

 darstellung der flora der vorwelt." In this numerous species 

 of Fucoidcs are given, mo.st of them from Brongniart. We 

 find the genus broken up and the species referred to various 

 sub-genera. These are taken from living genera which seem 

 to bear the closest resemblance to the fossil forms. Among 

 them are Chondria, Sargassum, Caulerpa, Delesseria, etc. A 

 single new species seems to be described, viz: Fucoidcs 

 cylindricus, while F. (^ranulatus is used to replace Algacites 

 s;ranulattis Schloth. 



The next publication bearing upon the subject was an 

 important one. It was Brongniart's " Histoire des vegctaux 

 fossiles, ou recherches botaniques et geologiques sur les 



