Bibliographical Notices. Bio 
In the marine turtles it completely covers the fourth ventricle, ex- 
tending back twice as far as in the alligator. In the frog it is ver- 
tical, while in the tailed Batrachians it is more or less blended with 
the optic lobes. In heloderma the cerebellum curves forward, but 
is not closely applied to the optic lobes, as in other lizards. Just in 
front of the cerebellum is the valvula cerebelli, which contains the 
decussating fibres of the fourth pair of nerves. 
The optic lobes are admirably represented in fifteen plates, which 
display the microscopic anatomy of this region of the brain in a 
striking manner, demonstrating a greater diversity of structure than 
would have been anticipated. This region of the brain in Ophidians 
appears to be characterized by an absence of the linear arrangement 
of the cells of the cortical layer, such as is seen in other reptiles and 
in Batrachians. In Chelonians there is a remarkable ganglion formed 
of large cells in the roof of the optic lobe over the ventricle, and on 
each side of the central group are other layers of small cells. These 
layers of cells are regarded as the origin of the optic nerves. Be- 
neath the optic lobes, in the peduncle, are the cells and fibres in 
which the oculo-motor nerve rises, though in the tailed Batrachians 
the origin of this nerve is not seen. In the axolotl some doubt 
appears to attach to the distinctness of the optic lobes. The optic 
thalami are seen one on each side of the V-shaped third ventricle, 
in front of the optic lobes. Beneath are the tuber cinereum and the 
cerebral hypophysis. 
The cerebral hemispheres are examined in somewhat less detail ; 
but the plates show a general correspondence of the parts in the 
several types. The corpus striatum is much larger in Lizards and 
Ophidians than in Batrachians ; and in the alligator this organ is 
relatively larger than in the heloderma. In the box-turtle the corpus 
striatum has about the same development as in lizards, 
Having thus treated in general terms of the chief parts of the 
central nervous system, the author prints an appendix on the ayer- 
age size of nuclei in the nerve-cells which are related to motor 
nerves, showing that the nuclei of the motor cells of the central 
nervous system have in the same individual a size which is pro- 
portional to the power in the related muscles. Similar relation of 
size in the nerve-cells is found in the spinal column to govern mus- 
cular development in the limbs; and the later plates are devoted to 
demonstrating the size of the nuclei in the cells connected with 
cranial nerves. 
In a second series the author promises to examine the minute 
anatomy of the basal parts of the brain. The list of plates gives 
their amplification and subject; while on the plates themselves, 
besides description and number of the negative, the power of the 
object-glass and its maker are mentioned. 
No words could do justice to the beauty of the plates or the value 
of the information they convey; and it is not too much to regard 
this work as opening a new era in research by substituting know- 
ledge of facts of microscopical structure for their interpretation by 
the hand of artist or author ; but we can scarcely hope to see many 
