28 



THE FROG 



which lies a white rod, made of the same soft, pulpy sub- 

 stance as the nerves, and called the spinal cord (Fig. 6, 

 sp. id), which ends behind in a thread-like prolongation 

 (/ t), some distance in front of the thighs. It will also be 

 found that the neural canal is continued, with a slightly 



Fig. 6. — iii-^--ci-Liun of a Fros in which the entire neural canal has been opened from 

 abuvu, and the I it. an (Z'r) and spinal cord (.f/. ri/) laid bare. The brain consists 

 c>f (iir,n.tiir\ lubijs (oi/. /), cerebral hemispheres (tr/'. /i), diencephalon {cfirn), 

 .iptic lulj'.s {o/'f.f), CL-reljelluni (c7'////), and medulla oblongata (;//(■(/. (j/^/), which 

 will lie rclerreil lu in Chapter X. The spinal cord end-s in a delicate prolonga- 

 tion, the rilain terminale ( /" /), Tlie nasal bi.nes f^/,i), eyes {e), auditory 

 ret;lijn ^if tfie skull (a//), trans\'erse processes of the nine \ertebra; (7'./ — 7-.Q), 

 iirostyle {i/.st) and ilia f/V) are indicated in outline, and serve as landmarks 

 fAfl'-r Huwes, slightly altered.) 



increased diameter, into the skull, and that the spinal cord 

 becomes continuous with the l>7'ai/i (/v), a complex organ 

 formed of several parts, which will he referred to hereafter. 

 General Structure of the Limbs. — A transverse section 



