592 Dale . — Observations on Gymnoascaceae . 
A comparison of the habitats of the various genera included 
in the Gymnoascaceae and Onygenaceae is also very suggestive 
in considering their affinities. For example, many species of 
Gymnoascus live either on the excrements of animals or on 
various parts of dead or living animals. G. ossicola and 
G. aurantiaca have been found growing on old bones. Eidam 
found G. Reessii growing on the dead pupa of Sphinx Gallii. 
G. umbrinus has been found on a dead cockchafer, G. candidns 
on the feathers of owls, G. setosus on an old bee’s nest and on 
an old wasp’s nest, which probably both contained excrements ; 
G. reticnlatus was found on the decaying horn of a cow, and 
G. myriosporus on the surface of the claws of birds of prey, and 
also on the excrements of these birds ; Ctenomyces grows on 
feathers, Onygena on horn ; Eidamella was obtained from 
the skin of a live dog, and is, according to Matruchot and 
Dassonville, related to other dermatophytes, e. g. Trichophytoii. 
Moreover, the genera and species included in the Endomy- 
cetaceae, the Gymnoascaceae, and the Onygenaceae fall into 
a series in which there is a gradually increasing complexity in 
the structure of the fructification. 
In Endomyces decipiens the asci are naked and solitary, and 
are produced on the ends of branching hyphae and show a 
tendency towards aggregation. 
In Gymnoascus candidus the asci, while still completely 
without investment, are aggregated together in dense masses, 
each mass being produced from a single pair of conjugating 
cells. In other species of Gymnoascus , in Ctenomyces , and in 
Eidamella the groups of asci are more or less enclosed in a 
loose investment of thick-walled, branching, and, in most 
cases, anastomosing hyphae. 
In Aspergillus and Penicillium the still more compact groups 
of asci are each surrounded by thick-walled hyphae, which 
form a continuous wall of pseudo-parenchyma — the peridium. 
In Onygena also the asci are enclosed in a complete invest- 
ment, which in some respects is more differentiated than that 
of the Aspergillaceae. 
In comparing the sexual organs of the forms under con- 
