endothrix

[ĕndō-thrĭks′]
n.
  1. A trichophyton, especially Trichophyton violaceum or T. tonsurans, whose spores and sometimes mycelia characteristically invade the interior of the hair shaft.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.