270 DESCRIPTIVE CATALOGUE 



it inhabits a different host from that attacked by his 

 original species, than to multiply specific names. 

 Upper Cretaceous ; Hokkaido, Japan. 



Presented hy Dr. M. 0. Slopes, 1910. 



Genus PETROSPH.ffiRIA, Stopes & Fujii. 

 [Phil. Trans. Roy. Soc. Lond., 1910 b, p. 6.] 

 Monotypio genus with the following species. 



Petrosphseria japonica, Stopes & Fujii. 



[Plate II.] 



1909-10. Petrosphceria japoniea, Stopes & Fujii, Proc. Roy. Soc. 

 Lond., vol. 81, p 599 (abstract), and Phil. Trans. Roy. Soc. Lond., 

 1910 b, pp. 4-6, pi. i, figs. 1-6. 



Microscopic fungus in which the " hyphse are septate, 2-4 fi 

 in diameter, the septa at right angles to the long walls. Many 

 cells of the hyphae irregularly swollen to a large size. These 

 swollen cells usually thickened, and forming round or irregular 

 nests of plectenchyma which has often extremely thick walla. 

 These clusters, entirely within the tissue- of the host, are 

 principally in tho periderm." 



Truo spore-formation at present unknown. 



Host. — Saururopsis, on tho apparently underground stems. 



HoBizoN. — Upper Cretaceous. 



Locality. — Hokkaido, Japan. 



Type.— British Museum (Natural History). 



The stem of the Angiospormic genus Saururopsis was found 

 to be thickly infested with septate hyphjs and also masses of 

 reproductive or resting cells (see text-fig. 22). 



No other fossil form is known with which this can be com- 

 pared, but resting masses of thickened cells are not uncommon 

 among living members of the SphaeriaceaD, with which it is 

 probable the fossil has some affinity. Whether the fossil was a 

 parasitic or saprophytic form is not determinable, but it appears 

 to have lived underground, for the part of the host it was in- 

 festing was a rhizome or underground stem. 



V. 11968. Holotype. Stopes & Fujii, 1910, Phil. Trans. Roy. 

 Soc. Lond., pi. i, figs. 1, 2, 3, -5, & 6. There is little 



