OF THE MARSIPOBRANCH FISHES. 
455 
Plate. 
Fig. 
Number of 
times 
magnified. 
21 
(As in last Plate.) 
55 
1 
The same ; thirteenth section. 
5 
„ 
2 
The same ; fourteenth section. 
5 
55 
3 
The same ; fifteenth section. 
5 
” 
4 
The same ; sixteenth section. 
5 
55 
5 
The same ; seventieth section. 
5 
55 
6 
The same ; eighteenth section. 
5 
55 
7 
The same ; nineteenth section. 
5 
55 
8 
The same ; twentieth section. 
5 
55 
9 
The same; twenty-first section. 
5 
22 
(As in last Plate.) 
55 
1 
The same ; twenty-second section. 
5 
55 
2 
The same ; twenty-third section. 
5 
55 
3 
The same; twenty fourth section. 
5 
55 
4 
The same ; twenty-fifth section. 
5 
55 
5 
The same ; twenty-sixth section. 
5 
55 
6 
The same ; twenty-seventh section. 
5 
55 
7 
The same ; twenty-eighth section. 
5 
55 
8 
The same ; twenty-ninth section. 
5 
55 
9 
The same ; thirtieth section. . . 
5 
23 
1 
Petromyzon fluviatilis (adult); solid vertical section of 
fore part. 
2* 
55 
2 
The same ; solid horizontal section of head. 
H 
55 
3 
The same; another similar section made on a higher 
plane. 
H 
55 
4 
Thirty-first thin section (as in Plates 20-22) .... 
5 
55 
5 
First similar solid section of a larger specimen 
3 
55 
6 
The same ; second section. 
3 
55 
7 
The same ; third section. 
3 
55 
8 
Petromyzon fluviatilis (larva, 6 inches long); thirteenth 
section (as in Plate 26). 
12 
55 
9 
The same ; fourteenth section. 
12 
