in Anatomy and Physiology. ‘ 257 
are the same that are met with in other vertrebrates in which 
_ limbs are developed ; but while in these the changes take place 
with great rapidity, in frogs generally the ichthyic condition of 
the cord in which there are no enlargements or bulgings, con- 
tinues for several months, the eggs being hatched in the spring, 
and the complete development taking place in the latter part of 
the summer. In bull-frogs, in this latitude at least, (42° north), 
it took not less than a year, as the tadpoles hatched in the spring, 
pass the following winter in the same condition, the metamor- 
phosis occurring during the following spring or summer 
Until the legs begin to be developed, the cord presents the form 
of an extremely elongated cone, and the bulgings as was noticed 
by Serres, are developed simultaneously with the legs. I have 
not, however, been able to confirm the statement made by him, 
and repeated by others, that the caudal portion of the cord is 
shortened as the legs and the bulgings are developed. According 
to my observations, no shortening takes place until the absorption 
of the tail commences, and this happens after the bulgings are 
formed and the legs have acquired their growth. The whole of 
the caudal prolongation, however, is not absorbed, a portion being 
persistent and eventually becoming enveloped by the elongated 
coceyx.”—p, 21-22. 
Section IV, treats of the peripheral portion of the nervous sys- 
em. Here Prof. Wyman’s researches have afforded results 
somewhat different from those of his predecessors. 
The subject of the cranial nerves is, as is well known, one of 
the most important connected with philosophical anatomy ; for 
upon the interpretation of these nerves, depend the various cranial 
theories some of which have become so noted. We cannot better 
present the subject than by giving Prof. Wyman’s table which 
exhibits an entimeration of the cranial nerves of man and mam- 
mals compared with those of the frog. 
‘* A. Cranial nerves. 
Mammals. Frog. 
I. Olfactory, - - . - - I. Olfactory. 
II. Optic, - - - - - II. Optic. 
Ill. Motor communis, - - - IIL. Motor communis. 
IV. Patheticus, - - - - IV. Patheticus. 
V. Trigeminus, on 
VI. Abducens, $arecombined, and form V. Trigeminus. — 
VIL. Facial, 
VIII. Auditory, - -  -  - VI. Auditory. 
IX. Glosso-pharyngeal, 
aS Vogt, comb’d & form VI. Vagus. 
XI. Acessory, 
_ XIL. Hypoglossal, e 
Srconp Series, Vol. XVI, No. 47.—Sept., 1853. 33 
