958 
MB. A. SANDEBS ON THE ANATOMY OF THE 
PLATE 60. 
Fig. 4. Transverse section through parts slightly behind the last. Taken from an 
older specimen of H. dorsalis. X 15^ diameters nearly. 
Fig. 5. Transverse section through the aqueduct of Sylvius and the trigonum fissum of 
a younger specimen. X 8-J- diameters nearly. 
Fig. 6. Transverse section taken farther behind, and falling through the main part of 
the commissura ansulata and the posterior part of the cerebellum. Taken 
from the same specimen as fig. 4. X 15| diameters nearly. 
PLATE 61. 
Fig. 7. Transverse section through the anterior part of the tuberculum impar. Taken 
from the same specimen as the last. X 15J- diameters nearly. 
Fig. 8. Transverse section through the posterior part of the tuberculum impar. Taken 
from the same specimen. X 15 J diameters nearly. 
PLATE 62. 
Fig. 9. Transverse section through the posterior part of the fourth ventricle. The 
extreme posterior end of the tuberculum impar, which projects over it, is 
not represented. This is taken from another specimen of the same species. 
X 37 diameters. 
Fig. 10. Transverse section through the posterior end of the fourth ventricle. Taken 
from the same specimen as fig. 8. X 37 diameters. 
Fig. 11. Transverse section taken close to the point of transition of the spinal cord 
into the medulla oblongata. Taken from the same specimen as the last. 
X 37 diameters. 
Fig. 12. Transverse section taken from the same specimen at a point a short distance 
behind the last. X 37 diameters. 
Fig. 13. Transverse section through the spinal cord of a younger specimen of the 
same species, to show the origin of the ventral roots of the spinal nerves 
X 37 diameters. 
PLATE 63. 
Fig. 14. Transverse section through the spinal cord of an older specimen of the same 
species, to show the origin of the dorsal roots of the spinal nerves. 
X 37 diameters. 
Fig. 15. Transverse section through the valvula cerebelli of the Ballan Wrasse (Ldbrus 
maculatus ). X 23 diameters. 
The tecta lobi optici and the upper part of the tori semicirculares are 
represented in outline. 
