454 
MR. W. K. PARKER ON THE SKELETON 
Description of the Plates. 
Plate. 
Fig. 
Number of 
times 
magnified. 
18 
1 
Petromyzon marinus; one-third grown; cranio-branchial 
skeleton; side view . .. 
H 
33 
2 
The same ; lower view. 
H 
33 
3 
Fore part of same ; upper view. 
H 
33 
4 
The same ; lower view.. 
H 
33 
5 
Vertical section of the same object. 
H 
33 
6 
■Lingual cartilage of the same specimen ; lower view 
6f 
3 3 
7 
The same ; upper view. 
6f 
33 
8 
Part of the same ; side view. 
6f 
19 
1 
Petromyzon marinus; recently metamorphosed (5 inches 
long); skull; upper view. 
12 
33 
o 
The same ; lower view. 
12 
33 
3 
The same (section); inner view. 
12 
„ 
4 
Petromyzon jluviatilis; large larva (6 inches long); 
skull; lower view. 
15 
33 
5 
The same ; upper view. 
15 
33 
6 
P. Jluviatilis; a younger larva, but of nearly the same 
size; first of a series of vertically-transverse sections 
through fore part. 
12 
3 3 
7 
The same ; second section. 
12 
20 
1 
Petromyzon Jluviatilis (adult); Jirst of a series of verti- 
cally-transverse, thin, transparent sections .... 
5 
33 
2 
The same ; second section. 
5 
33 
3 
The same ; third section. 
5 
3 * 
4 
The same ; fourth section.. 
5 
” 
5 
The same ; fifth section. 
5 
33 
6 
The same ; sixth section. 
5 
33 
7 
The same ; seventh section. 
5 
33 
8 
The same ; eighth section. 
5 
33 
9 
The same ; ninth section. 
5 
33 
10 
The same ; tenth section. 
5 
» 
11 
The same ; eleventh section. 
5 
33 
12 
The same ; twelfth section. 
5 
