APPENDIX VIII. 315 



system. The opercular parts develop backwards, the 

 lower jaw forwards, without, however, reaching the ex- 

 tremity of the snout. The lower extremity of the dorsal 

 cord rises. The odd fins take their shape definitely and 

 receive their rays. The pectoral fins are very large in 

 proportion. The fringes of the capillary arteries begin to 

 develop upon the branchial arches. The metallic pigment 

 of the choroid appears. The swimming bladder unfolds. 

 The cartilaginous skeleton begins to turn to bone, and the 

 rudiments of the teeth appear in the mouth. 



