245 
sory ribs (intermuscular bones) have been 
rotated forwards so that their exact length 
may be indicated. The dotted line shows 
the extent of the asymmetry. 
Fig. 11. The eighth trunk vertebra viewed from the 
front of a 64cm. Plaice. Natural size. The 
accessory ribs have been rotated forwards in 
order to introduce their full length. The 
dotted line shows the departure from the 
symmetry. 
Fig. 12. The twelfth trunk vertebra of a 52cm. Plaice 
seen in optical longitudinal section, the 
ocular or right half of the centrum and right 
neural arch having been ground away. 
Natural size. The figure illustrates the 
amphicoelous character of the centrum, and 
the shape and extent of the notochordal 
spaces. 
Fig. 13. The fourteenth or first caudal vertebra of a 
52cm. Plaice seen from the front. Natural 
size. The dotted line indicates the depar- 
ture from the symmetry. The same ver- 
tebra is shown in side view in fig. 18. 
Fig. 14. Moist dissection from right side of caudal fin 
and termination of vertebral column of a 
34cm. Plaice. Natural size. The fin rays 
have been disarticulated from the fibro- 
cartilaginous pad. 
Fig. 15. Dissection from right side of posterior extremity 
of notochord and caudal fin supports of a 
young Plaice of I7mm. Drawn with 
camera. x 15. Notochord as yet unossified, 
but faint vertebral constrictions (6 shown in 
fig.) have appeared. The neural and haemal 
