SKELETON OF EEGALECUS AEGENTEUS. 



31 



interspinous bone to the demi- 



vertebra. 



mclc. Meckel's cartilage. 



m.eth. Mesethmoid. 



m.n.c- Meso-nasal cavity. 



m-pt. Metapterygoid. 



ms.pt. Meso-pterygoid. 



mx. Maxilla. 



my. Spinal cord. 



na. Nasal. 



n.'pl. Neural plate. 



H.pr. Neural process. 



n.s. Neural spine. 



o.c^. Dorsal ]r . c ■ ■.. ^ i i 



>tacet 01 occipital condyle. 

 o.c". Ventral/ ^ ^ 



o.in. Os innominatum. 



op. Opercular. 

 (yp.o. Opisthotic (op.o^, ascending pro- 

 cess ; ojJ.o^, anterior process ; 

 op.o^ posterior process; op.o\ 

 descending process). 

 o.s. Orbitosphenoid. 

 pa. Parietal. 

 pa.br. ^~^. Parabranchials. 

 pas. Parasphenoid. 

 pc.f. Pectoral fin. 

 p.cl. Post-clavicle. 

 p.eth. Par- (or ecto-) ethmoid. 

 ph.br. 1-4. Pharyngo-brauchials. 

 pi. Palatine. 

 pmic. Alveolar jjortion of premaxilla. 

 pmx' . Nasal process of premaxilla. 

 p.n. Prenasal cartilage. 



p.op. Preopercular. 

 p.or.p. Postorbital pillar. 



pr.o. Pro-otic. 

 pr.or. Pre-orbitals. 

 pt. Pterygoid. 

 pto. Pterotic. 

 p.tm. Post-temporal. 

 pv.f. Pelvic fin. 

 pzy. Posterior zygapophysis. 

 qu. Quadrate. 

 r (in figs. 22 and 24). Strengthening ridges 



of centrum. 

 r^-r' (in fig. 4). Cutaneous ridges. 

 r'' (in fig. 20). First rib. 

 sc. Scapula. 

 s.cl. Supra-clavicle. 

 s.o. Supra-occipital. 

 s.op. Subopercular. 

 spo. Sphenotic. 

 sy (in fig. 14 and 15). Symplectic. 

 sy.sy^ (in fig. 19). Symphyses of inno- 

 minate bone. 

 t.cr. Tegmen cranii. 

 tr.pr. Transverse processes, numbered 



in fig. 20. 

 u.hy. Urohyal or basi-branchiostegal. 

 F'. Foramen for orbitonasal nerve. 

 F^. Foramen for mandibular nerve (?). 

 vo. Vomer. 

 X. Foramen for vagus. 

 A'^-A'^. Cartilaginous nodules on the dorsal 

 ends of the cerato-branchials. 



Cartilage coloured mauve. 

 Cartilage-bone coloured yellow. 

 Periosteum, ligament, &c., coloured blue. 



