270 
some cases there was an outer part composed of two or three layers. 
The forms were referred to the genus Archagaricon (p. 226), with live 
species, as follows: A. bulbosum , A. globuliferum , A. radiatum , A. den- 
driticum , and A. conglomeration. The first (A. bulbosum) is the only spe¬ 
cies illustrated. It is probable that these bodies are really fungoid in 
tlieir nature, but it seems scarcely justifiable to make so many species. 
In 1877 Worthington G. Smith referred to this paper* and said 
that while one of the figures might pass for a species called by himself 
Peronosporites antiquus , u drawn by a bad draftsman, unacquainted with 
fungi,” the descriptions were too indefinite to determine what the writers 
really had in mind. 
In this same papert Mr. Smith described a fungus under the name 
mentioned above. lie observed it in the stem of a species of Lepido- 
dendron from the Coal Measures, and described the liyplue as septate 
and bearing oogonia, which contained zoospores. Further, he stated 
that an enlargement of the fossil to 400 diameters showed the oogonia 
to be the same in size and character as similar structures belonging to 
the potato fungus. The average number of zoospores in each he said 
was also the same, namely, seven or eight. While these observations of 
Mr. Smith have been criticised in many quarters,:f it is probable that the 
body described is a fungus. Mr. Oarrutliers considers it to be such, 
without question. In his “Diseases of Field and Garden Crops,” pub¬ 
lished in 1884, Mr. Smith referred to the criticisms that had been passed 
upon the fossil from time to time, and reiterated his statement that traces 
of zoospores are visible in the oogonia. In Massee’s recent volume,§ the 
subject is again discussed, and the conclusion is that the species is 
perhaps as well placed in the Peronosporece as in the Sap ro leg niece , 
where Williamson thought it belonged. 
It should be mentioned here that DeBary has questioned the ac¬ 
curacy of Smith’s observations in regard to the presence of oospores 
and zoospores in the living Phytophthora infestans. Sexual organs, 
however, have been observed in another species of the genus (P. om- 
nivora ),|| and their presence may yet be demonstrated to the satisfac¬ 
tion of all in P. infestans. DeBary says that u septa occur in the 
mycelium of P. infestans , especially when old, but they are always 
isolated and very irregular.” ]] The imperfect preservation of the fossil 
Peronosporctes probably accounts for the conflicting statements that 
have been made in regard to it. It is, too, scarcely to be expected that 
* Gard. Cliron., new ser., Vol. viii, London, 1877, p. 499. 
t A fossil Pcronospora (Peronosporites antiquus W. Sin.). 
t By Murray in the Academy, Nov.-17, 1877, who denied the existence of the zoo¬ 
spores; and by Williamson in the Philosophical Transactions of the Royal Society of 
London Vol. clxxii, p. 299. The latter stated that the relations of the fungus 
were more probably witli Saprolegnice than Peronosporece. 
British Fungi: Phycomycotes and Ustilagineie, London, 1891, pp. 213-216, 
|| Bennett & Murray, Cryptogamic Botany, 1889, p. 327. 
H Jour Roy. Agric. Soc. England, Vol. xii, London, 1876, p. 262. 
