Comparative Anatomical Study on The Ciliary Ganglion of Snakes (Reptilia - Squamata - Ophidia)

In the present study, there is a well developed ciliary ganglion. In Natrix tessellata and Coluber rogersi , this ganglion consists of two types of neurons, large ones at the periphery and smaller ones at the center. In Malpolon monspessulana, there is only one type of neurons; i.e., there is no regional differentiation. The ciliary ganglion in Natrix tessellata has two roots; radices ciliares brevis and longa, whereas in Coluber rogersi and Malpolon monspessulana, has only one root; mixed root in Coluber and radix ciliaris brevis in Malpolon. In the three species studied, there is no direct connection between the ciliary ganglion and the carotid plexus, i.e., there is no sympathetic root for the ganglion. In Natrix tessellata and Coluber rogersi, two ciliary nerves arise from the ciliary ganglion, whereas in Malpolon monspessulana, there is a single ciliary nerve.