244 



angles from its upper border. Tlie lower 

 border of the bar in the figure is therefore 

 the dorsal border, and the face shown is the 

 anterior face. The first pair of branchiostegal 

 rays has been turned forwards. They really 

 pass straight backwards in the mid-ventral 

 line. The branchiostegal rays are numbered 

 from before backwards, and have been dis- 

 played. 



Fig. 7. Dorsal (moist) dissection of the branchial arches 

 of a 34cm. Plaice. Natural size. The arches 

 have been flattened out and displayed. On 

 the right side the three pharyngo-branchials 

 forming the superior pharyngeal bone have 

 been separated and left attached to their 

 respective arches, but on the left that bone 

 is represented intact drawn from its oral 

 surface. The arches are numbered from 

 before backwards (i.-v.). 



Fig. 8. Lateral (moist) dissection of the right pectoral 

 girdle and fin of a 34cm. Plaice. Natural 

 size. The " inter-clavicle " in front is shown 

 in its correct position relative to that of the 

 pectoral girdle. The fin rays have been 

 separated from the two fibro-cartilaginous 

 pads with which they articulate. 



Fig. 9. Lateral (moist) dissection of the right pelvic 

 girdle and fin of a 34cni. Plaice. Natural 

 size. The fin rays are represented dis- 

 articulated from the fibro-cartilaginous pad. 



Plate III. 



Fig. 10. First or atlas vertebra viewed from the front of 

 a 52cm. Plaice. Natural size. The acces- 



