Comparative anatomical studies on the cranial nerves of the fully formed embryos of the Nile tilapia Oreochromis niloticus (Ostiechthyes-Cichlidae). I. Nervus glossopharyngeus

The organization of the roots, ganglia and the peripheral distribution of the cranial nerves of the fully formed embryos of Oreochromis niloticus are examined in the transverse serial sections. These nerves carry fibers, which were also analyzed. The results of this study demonstrated that the glossopharyngeal nerve originates by means of only one root, which leaves the cranium through the glossopharyngeal foramen. This nerve gives fibers (visceromotor) to the first internal and external levator arcus branchialis muscles. There is a single epibranchial (petrosal) ganglion located extracranially. Nervus glossopharyngeus has three rami; pharyngeus, pretramticus and posttrematicus. The ramus pharyngeus carries only viscerosensory fibers; general for the pharyngeal epithelium and special ones for the pseudobranch. General viscerosensory fibers are also carried by rami pretrematicus and posttrematicus for the pharyngeal epithelial lining. The special sensory fibers are carried by the ramus pretrematicus for the taste buds and by ramus posttrematicus for the gill filaments. The ramus pretrematicus also carries visceromotor fibers for the first adductor arcus branchialis and to the first obliquus ventralis muscles.

Prenatal development of the sound transmitting apparatus in different embryonic stages of Malpolon monsspesulanus (squamata-serpentes)

The developmental investigation of sound transmitting apparatus is important in understanding the ontogenetic processes behind morphological diversity. The development of sound conducting apparatus was studied in Montpellier snake; Malpolon monspessulanus at 6.5, 7.2, 8.3 and 9.3 cm total body lengths using light microscopy study. The columella auris firstly appeared as undifferentiated rod shape mesenchymal cells. As the growth proceeded, it chondrified and differentiates into two main parts. In addition, the viscerocranium components which participate in formation of sound transmitting apparatus undergo critical organization. In more advanced stages, procartilagenous stylohyal chondrified and fuse with the well organized quadrate. These data considered as a base for functional and molecular mechanisms of sound transmitting apparatus studies and identification of diseases that may infect them.

The Terminal and Vomeronasal Nerves of Montpellier Snake, Malpolon monspessulana (Colubridae, Ophidia, Squamata)

The montpellier snake, Malpolon monspessulana, used in the current work in order to study the nervi terminalis and vomeronasalis. The vomeronasal organ or Jacobson’s organ is a part of the olfactory apparatus. This organ is innervated by the terminal and vomeronasal nerves. These nerves emerge from the sensory epithelium of Jacobson’s organ simultaneously. The bundles of the terminal and vomeronasal nerves traverse together the cavity of the nasal capsule in their way to the brain. These nerves bear scattered ganglionic cells which represent the ganglion terminale. They leave the capsule through the foramen olfactorium advehens. The terminal and vomeronasal nerves are connected with the olfactory nerve and enter the olfactory formation of the forebrain.