Brooks — The Osteology and Arthrology of the Haddock. 193 



The fin-rays resemble those of the pectoral fin, but are much 

 shorter, and only six in number. The difference between the bases 

 of the inner and outer portions is less marked than in the pectoral. 



The otoliths are not described in this Paper, as they belong 

 more properly to the anatomy of the ear than to the general 

 osteology. ; 



EXPLANATION OP THE FIGURES ON PLATES V. to IX. 



Fig. 1. The Skull from the side. — 1, supra-occipital; 2, pterotic ; 

 3, ex-occipital ; 4, opisthotic ; 5, basi-oocipital ; 6, prootic ; 7, para- 

 sphenoid ; 8, vomer ; 9, articular surface for palate bone ; 10, ethmoid 

 — the line points to the depression for the attachment of the maxillo- 

 ethmoidal ligament; 11, prefrontal — the line points to the articular 

 cavity for the lachrymal ; 12, frontal ; 13, sphenotic ; 14, placed in the 

 space for the interorbital septum, points by a line to the alisphenoid ; 

 a, foramen for glossopharyngeal nerve ; h, articular cavity for head of 

 hyomandibular. 



Fig. 2. The Skull from above. — 1 to 11, as in fig. 1 ; 10', apex of 

 pyramidal portion of ethmoid; "15, epiotic ; 16, parietal. 



Fig, 3. The Skull from behind. — 1, supra-occipital ; 2, epiotic ; 

 3, pterotic ; 4, exoccipital — the line ends just above the foramen for 

 the vagus nerve ; 5, opisthotic ; 6, basi-occipital ; 7, foramen for first 

 spinal nerve. 



Fig. 4. Superficial Dissection of the Left Side of the Head. — 1, points 

 by five lines to the infra-orbital bones ; 2, prefirontal ; 3, hollow in 

 nasal bone ; 4, lachrymal ; 5, premaxilla ; 6, maxilla ; 7, angle of 

 mandible ; 8, inter-operculum — beneath this are seen the branchio- 

 stegal rays ; 9, condyle of quadrate ; 10, pre-operculum ; 11, sub- 

 opercidum ; 12, operculum; 13, post -temper al ; 14, ridge of pterotic ; 

 15, epiotic; 16, suture between supra-occipital and frontal; a, piece of 

 skin left surrounding the double nasal opening ; b, b', anterior, and 

 c, posterior, maxillo-mandibular ligaments ; d, ligament between inter- 

 operculum and . mandible ; e, temporal muscle ; /, abductor muscle 

 inserted into hyomandibular ; g, abductor of the operculum. 



Fig. 5. Left Palato-quadrate Arcade, ivith the Hyomandibular and Gill 

 Cover, seen from the outer side. — 1, palate ;-2, entopterygoid ; 3, meta- 

 pterygoid ; 4, ectopterygoid ; 5, quadrate ; 6, interoperculum ; 7, sub- 

 operculum ; 8, preoperculum ; 9, symplectic ; 10, triangular intercalary 

 cartilage; 11, operculum;- 12, hyomandibular; r^. point of attachment 



