258 Dr. Burnett's Reviews and Abstracts 
B. Spinal nerves of the Frog. 
I. Hypoglossal. Vil. 
ot Brachial. Crural. 
IV X. Coccygeal. 
ve“ ‘Abadmitial: 
From this table it will be seen that the hypoglossal nerve in 
the frog occupies a position somewhat anomalous, forming, as it 
does, the first pair of the spinal series.” —p. 24. 
In his description of the optic nerves, Prof. Wyman has some 
interesting remarks on the relations of the optic lobes to the func- 
tion of vision. He says: “Many observers have shown, by dis- 
section, that blindness of long standing is followed by atrophy of 
the optic.lobes, (agreeably to the well-known law of atrophy fol- 
lowing disuse), and that extensive lesions of the lobes are attended 
by either impairment or loss of vision. In recent dissections of 
He then alludes to the instances of blind animals found in cav- 
erns and other dark places, in which the optic lobes are not un- 
developed. ut we do not recognize the correctness of this 
last sentence, and cannot perceive how the plural function of 
these lobes can be inferred from the data cited. On the other 
hand, considering the stability of typical forms in structure, and 
the unvarying relations of grand types, even in distinct systems 
of tissue, we should indeed not look for any deviations from these 
fundamental plans to fit a single condition, and especially where 
all the other relations of life are as usual. The doctrine of final 
causes, although fully sustained by the general conditions of or- 
ganization as manifested under typical plans, has many an instance 
in living forms which would be wholly irreconcilable, did we not 
bear in mind its reference to a type idea. ‘The mammary glan 
exists in man as well as in woman, and yet it has but one tunc- 
tion, its presence in man being in virtue of a typical plan. : 
e pass over the details npon the cranial nerves contained ™ 
this section. Not a few of them are new, and the whole carried 
out in all their relations with an almost wonderful minuteness- 
