In the spinal ganglia of two species of reptiles (gecko and lizard) the volume of the perikaryal satellite cell sheath was found directly proportional both to the volume and surface area of the related neuronal body. This result agrees with that obtained in a previous research on two species of mammals (cat and rabbit). A quantitative balance between neuronal bodies and their associated glial tissue therefore exists also in the spinal ganglia of zoological species phylogenetically quite distant from mammals. The quantitative relationship between glial and nerve tissue was found to be lower in the gecko and lizard than in the cat and rabbit. This difference could have a phylogenetic significance, and/or it could be explained by the lower metabolic rate in the nervous system of the poikilotherms in respect to mammals.