THE ONTOGENY OF NASAL CHEMICAL SENSES IN GARTER SNAKES

The development of the nasal chemical senses of reptiles is of particu lar interest since evidence suggests that neonatal reptiles use both t heir olfactory and vomeronasal systems. This review focuses on the emb ryonic development of these nasal chemosensory systems in garter snake s (Thamnophis spp.). Three approaches have been used to examine develo pment: (1) Normal morphological studies, (2) H-3-thymidine autoradiogr aphic studies, and (3) metabolic mapping of the accessory and main olf actory bulbs with cytochrome oxidase histochemistry. In addition, gart er snake embryos have been grown in vitro to facilitate experimental p rocedures. The results of these studies show that reptiles are a rich and diverse group for investigating the developmental processes that f orm the neurobiological basis for naturally occurring chemosensory-med iated behaviors.