ANATOMY OF THE MELANONIDAE 



27 



first to the tenth. In batrachoidiiforms it is usually between 

 the third and fourth neural spines and in lophiiforms the 

 eighth and ninth or more posterior neural spines. 



Supraneurals, preceding the first dorsal fin are rarely 

 present in gadiforms (Patterson & Rosen, 1989). 



Baudelot's ligament (Figs 13A,B) stems from the lateral 

 cavity of the first vertebra to connect with the supracleithrum. 

 The retractor dorsalis muscle originates from the fourth 

 through sixth vertebrae; on the sixth it is attached to the 

 leading edge of the parapophysis (Fig. 13B). 



Brain (Fig. 16). 



The brain of Melanonus is situated well forward, the telen- 

 cephalon and anterior part of the mesencephalon being 

 anteriorly displaced beyond the cranial cavity so as to lie in 

 the orbital cavity formed by the enlarged pterosphenoids. 

 The olfactory and optic lobes are large. The olfactory tracts 

 are well separated and each tract is short and thick compris- 

 ing at least twelve separate nerves each of which branches to 



feed the individual laminae of the nasal rosette. The olfactory 

 bulb is large and lies against the lobe which is narrowly 

 separated by a fissure from the laterally situated optic lobe. 

 Upon leaving their respective lobes ventrally, the optic tracts 

 cross and travel directly laterad a short distance to the eyeball 

 which is only narrowly separated from the telencephalon. 

 The cerebellar corpus is flat and lies pointing anteriorly 

 between the optic lobes. This is a unique condition among 

 gadiforms (noted by Marshall & Cohen, 1973 as diagnostic of 

 the Melanonidae), normally the corpus is bulbous and ele- 

 vated (Okamura, 1970) or lies posteriorly along the cerebel- 

 lar crest. The cerebellar crest is flat and elongate flanked 

 ventrolaterally by extensive trigeminal lobes. The cerebellar 

 body extends posteriorly to entirely overlap the vagal lobes 

 along the basal part of the medulla oblongata, also a unique 

 gadiform condition. The granular eminence is large but not 

 laterally extended. Ventrally, the inferior lobes, pineal body, 

 hypophysis and vascular sac are all well-developed. 



The brains of some gadoids and macrouroids have been 

 described by Svetovidov (1953), Okamura (1970) and Howes 



nr 



mo 



nVJI 



ge nV nau n ^ n % 



Fig. 16. Melanonus zugmayeri brain in A, dorsal and B, lateral views. In A, the pathways of the optic tracts beneath the lobes are indicated 

 by dashed lines and the margin of the prootic is indicated by dashed lines lateral to the trigeminal-facial nerve complex. 



