. Bulletin of the Natural History Museum Zoology. 28 & Crimmen (1990) and of those published descriptions Breg- maceros has the most similar overall morphology. Like that of Melanonus the brain is elongate with extensive trigeminal- facial lobes, a long cerebellar crest and closely connected olfactory bulb and lobe. However, there are major differ- ences in the relatively small size of the olfactory and inferior lobes and in the cerebellar corpus being orientated posteri- orly along the crest, having a posterolateral fissure and leaving the midline of the optic lobes exposed. Anterior plac
. Bulletin of the Natural History Museum Zoology. 28 & Crimmen (1990) and of those published descriptions Breg- maceros has the most similar overall morphology. Like that of Melanonus the brain is elongate with extensive trigeminal- facial lobes, a long cerebellar crest and closely connected olfactory bulb and lobe. However, there are major differ- ences in the relatively small size of the olfactory and inferior lobes and in the cerebellar corpus being orientated posteri- orly along the crest, having a posterolateral fissure and leaving the midline of the optic lobes exposed. Anterior placement of the forebrain was considered a gadiform character by Svetovidov (1948) and among gadoids there is a tendency for the brain to be shifted forward. In those few morids investigated and in macrouroids the fore- brain is generally confined to the cranial cavity. In some other paracanthopterygians (ophidiiforms, Howes, 1992 and per- copsids pers. obs.)the telencephalon lies in the orbital cavity as in Melanonus. It is problematic as to which features of gross brain morphology can be used as phylogenetic markers. The degree of separation of the olfactory bulb from the lobe is variable in gadiforms (discussed by Howes & Crimmen, 1990) but the plesiomorph condition, possessed by Melanonus, is seemingly for them to be closely associated. The shape of the olfactory lobe is also a highly variable feature and one that might, at least, be generically characteristic. Summarising data from gadoid brain descriptions given by Svetovidov (1953) it appears that elongate and short cerebral crests are equally distributed amongst the taxa he studied. A short, tall cerebral crest, common to gadoid brains, is also the common condition among paracanthopterygians. However, the granular eminence, although often large is laterally extended only in the Gadidae (sensu Dunn, 1989 and Howes, 1991b). Swimbladder, viscera and body musculature (Fig. 17). The swimbladder is an elongate ellipsoidal, t
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