+---------------+---------------+----------------+---------------+-------------+ | Vertebrae. | Occipital. | Parietal. | Frontal. | Nasal. | +===============+===============+================+===============+=============+ |Centra. |Basioccipital. |Basisphenoid. |Presphenoid. |Vomer. | +---------------+---------------+----------------+---------------+-------------+ |Neurapophyses. |Exoccipital. |Alisphenoid. |Orbitosphenoid.|Prefrontal. | +---------------+---------------+----------------+---------------+-------------+ |Neural Spines. |Supraoccipital.|Parietal. |Frontal. |Nasal. | +---------------+---------------+----------------+---------------+-------------+ |Parapophyses. |Paroccipital. |Mastoid. |Postfrontal. |None. | +---------------+---------------+----------------+---------------+-------------+ |Pleurapophyses.|Scapular. |Stylohyal. |Tympanic. |Palatal. | +---------------+---------------+----------------+---------------+-------------+ |Haemapophyses. |Coracoid. |Ceratohyal. |Articular. |Maxillary. | +---------------+---------------+----------------+---------------+-------------+ |Haemal Spines. |Episternum. |Basihyal. |Dentary. |Premaxillary.| +---------------+---------------+----------------+---------------+-------------+ | Diverging |Fore-limb or |Branchiostegals.|Operculum. |Pterygoid and| | Appendage. | Fin. | | | Zygoma. | +---------------+---------------+----------------+---------------+-------------+ Owen's reasons for considering the pectoral girdle and the fore-limb part of the occipital vertebra are as follows. In fish the pectoral girdle is slung to the skull by means of the post-temporal bone (supra-scapula, according to Owen) which abuts on the occipital arch. In _Lepidosiren_, whose skeleton resembles the archetype in many ways, the pectoral girdle is likewise attached to the occipital segment.