| Nerves | Diameter (mm) | Place of Origin | |
|---|---|---|---|
| I. | olfactory | relatively thick, 2mm | rostroventral part of the telencephalon |
| II. | optic | very thick, 2.5mm | ventral side of the telencephalon, from the chiasma opticum |
| III. | oculomotor | relatively thin, 1mm | behind the hypophisis |
| IV. | trochlear | very thin, 0.5mm | behind the optic tect |
| V. | trigeminal | middle size,1mm | rostrolateral part of the rhombencephalon |
| VI. | abducens | could not be observed | |
| VII. | facial | could not be observed | |
| VIII. | statoacoustic | very thick, 3mm | rostrolateral part of the rhombencephalon, behind the nerve V. |
| IX. | glossopharyngeal | thin, 1.5mm | caudolateral part of the rhombencephalon |
| X. | vagal | thick, 2.5mm | caudolateral part of the rhombencephalon |