The cellular changes associated with specific lesions of the pox group of animal virus diseases are associated with minute, uniform, filter-able granules in enormous numbers, which are considered by some to represent the viruses concerned. These granules are referred to by a variety of confusing names, such as elementary corpuscles, specific granules, Borrel bodies, etc. A terminology is recommended for these structures in the various diseases in which they occur (variola-vaccinia, fowl-pox, molluscum contagiosum, etc.), under the generic title BORRELIOTA, which acknowledges their first discoverer, Borrel, and, by the suffix iota, signifies smallest particle. This term is non-committal as to the biological status of the granules. The proposed terminology is as follows: Borreliota variolae hominis: specific corpuscles of variola (Paschen bodies, elementary corpuscles). Borreliota variolae bovis: specific corpuscles of vaccinia (Paschen bodies, elementary corpuscles). Borreliota variolae equi: spe-cific corpuscles of horse-pox. Borreliota variolae porci: specific corpuscles of swine-pox. Borreliota variolae ovium: specific corpuscles of sheep and goat-pox. Borreliota mollusci: specific corpuscles of molluscum contagiosum (Lipschutz corpuscles). Borreliota avium: specific corpuscles of fowl-pox (Borrel corpuscles).