PLATE X 



Fig. 1. The superficial bones of the right or upper side of the head of the Common 

 Sole. 



Fig. 2. The superficial bones of the left or lower side. 

 Eefereiice letters : 



Jim, hyomandibular. 



ms, mesopterygoid. 



mt, metapterygoid. 



m, mandible. 



pt, pterygoid. 



pa, palatine. 



s, symplectic. 



q, quadrate. 



x, maxilla. 



px, pre maxilla. 



o, opercular. 



po, preopercular. 



io, iiiteropercular. 



so, subopercular. 



Fig. 3. The bones of the branchial arches and paired fins, lateral view. 

 Fig. 4. The bony branchial arches spread out and seen from the dorsal side. 

 Eeference letters and numbers : 



66 1, 1st basibranchial. 



66 2, 2nd ditto. 



663, 3rd ditto. 



6A, basihyal. 



Tih, hypohyals. 



ch. ceratohyal. 



c6 1, 1st cerate-branchial. 



c6 2, 2nd ditto. 



Ip, lower pharyngeal. 



up, upper pharyngeal. 



2, stylohyal. 



3, epihyal. 



8, 1st pharyngobranchial. 



9, 1st epibranchial. 

 11, 1st hypobrancbial. 



14, 2nd epibranchial. 



16, 2nd hypobrauchial. 



17, 3rd pharyngobrauchial. 



18, 3rd epibranchial. 



19, 3rd eeratobranchial. 



20, 3rd hypobranchial. 



21, 4th epibranchial. 



25, post-temporal. 



26, supra-clavicular. 



27, clavicle. 



28, jugular. 



29, scapulfi. 



30, coracoid. 



31, pubic. 



Fig. 5. The skull, showing the separate bones and their sutures, from the right side. 

 Fig. 6. The same from the left side. 

 Fig. 7. The same from the dorsal side. 

 Fig. 8. The posterior surface. 

 Eeference letters : 



6.0. 



s.o. 



ex.o. 



ep.o. 



pt.o. 



op.o. 



pr.o. 



sp'.o. 



basioccipital. 



supraoccipital. 



exoccipital. 



epiotic. 



pterotic. 



opisthotic. 



prootic. 



sphenotic. 



pa. parietal. 



l.f. left frontal. 



r.f. right frontrJ. 



pa.s. parasphenoid. 



vo. vomer. 



tries, e. mesethmoid. 



r.ect.e. right ectethmoid. 



l.ect.e. left ditto. 



