TRICHOPHYTONEAE 459 



media. The colony is wholly woolly or velvety but with long radial strands 

 beyond the margin. The positions of T. depressum, Achorion Arloingi, Aleu- 

 risma Guilliermondi, and T. chosenicum are not clear, as these species have 

 been inadequately described, but from such meager data as are available they 

 appear to belong in this group. 



Returning to the line which diverged in E. lacticolor, we find that the 

 nodular organs are highly developed, and spirals are absent on Sabouraud media 

 although still present on other media ; the colony still has a depressed center. 

 E. gramdosum shows further degeneration by the disappearance of both clostero- 

 spores and spirals on Sabouraud media although the latter are still produced on 

 other media. The closterospore has apparently coiled and degenerated into 

 the nodular organ, the individual cells of which germinate as do the cells of 

 the closterospore ; the colony with a crater and radial folds has been retained. 

 Along with this degeneration, the organism has become adapted to the horse, 

 rarely occurring as an evanescent lesion of the glabrous skin of man, although 

 still easily inoeulable into the guinea pig. In E. eriotrephon the spirals have 

 completely disappeared, and the colony has become smooth, light gray and 

 cerebriform on Sabouraud conservation agar. This species has become adapted 

 in man, producing vesicular lesions and inoeulable with difficulty to the guinea 

 pig. It forms the transition to Favotrichophyton. 



To return to the primitive stage represented by Ectotrichophyton mentag- 

 rophytes and E. circuluscentricum, we find a line remaining wholly in the epi- 

 dermis, often producing vesicles but very rarely pustules, never kerion or sycosis. 

 Perhaps the most primitive line within the genus Epidermophyton is the E. 

 scdmoneum-persicolor group, which produces papular lesions of the type of 

 eczema marginatum in tinea criTris and vesicular lesions in the beard but no 

 sycosis. Traces of nodular organs are found in E. persicolor, while the mor- 

 phology of E. salmoneum is almost wholly unknown. E. plurizoniforme and E. 

 lanoroseum seem to continue this line, with gradual degeneration of clostero- 

 spore and aleurospore although both these spores are still present, the former 

 becoming smaller and less abundant. Another line in the genus is E. ruhidum 

 in which degenerate nodular bodies and closterospores are still occasionally seen 

 and chlamydospores are abundant. The lesion is in part pustular, the or- 

 ganism not being inoeulable into guinea pig. In E. rulrum the closterospores 

 are present and well developed, but no traces of spirals or nodular organs 

 remain ; the lesion is vesicular but not pustular, and the fungus is still in- 

 oeulable into guinea pig. In E. purpureum, closterospores are rare and poorly 

 developed ; aleurospores are abundant. The group of species of Epidermo- 

 phyton which never become pink or reddish, in which we find well-developed 

 spiral hyphae and closterospores but no trace of nodular organs, is adapted to 

 man and produces only a very evanescent lesion on experimental animals, with- 

 out attacking the hair. E. floccosum still produces spirals on complex carbo- 

 hydrate media although these are absent when it is grown on Sabouraud media ; 

 closterospores are abundant and somewhat specialized, thin-walled ; this species 

 is highly adapted to the inguinocrural region of man, not inoeulable to 

 guinea pig. 



