82 



Lumpfish, and called attention especially to the fact, that 

 the chord was distinctly and unequivocally enlarged at the 

 origin of each of the several pairs of spinal nerves. 



Cuvier, in the last edition of his Lectures on Comparative 

 Anatomy (Vol. III. p. 175) has made particular reference to 

 these enlargements, but Prof. Owen more recently, in his own 

 published Lectures, denies the correctness of Cuvier's statement, 

 as follows: — "Although many fishes show a slight enlarge- 

 ment at each junction of the nerve roots with the myelon, the 

 anatomical student will look in vain in the recent Eel or Lump, 

 fish, for that ganglionic structure of the myelon, which the 

 descriptions of Cuvier might lead him to expect." (Vol. II. 

 p. 173.) In the present instance the description of Cuvier is 

 entirely confirmed. 



Gall and Spurzheim were among the first to insist upon the 

 fact, that the spinal chord consisted of a series of ganglia, and 

 compared it to, and identified it with, the ganglionic chain of the 

 invertebrate animals ; or to use another and more recent expres- 

 sion, regarded the spinal chord of vertebrates and the ganglionic 

 chain of Articulates as liomologous. This position, somewhat 

 modified, has been more recently maintained by Dr. Carpenter, 

 who does not hesitate to identify, (to homologize,) the vertebrate 

 brain, (excepting the cerebral lobes and cerebellum,) with the 

 ganglia of the head of invertebrate animals. (See General and 

 Comparative Physiology^ 3d edition, p. 1025.) In doing this he 

 does not seem to have kept in mind the distinction between 

 homology and analogy ; which he has failed to do in other 

 instances in the same book, (p. 994,) e. g. where he regards the 

 arms of Hydra as homologous with the muscles of the throat in 

 Vertebrates. He might with equal propriety have identified 

 the arms of man, the trunk of an elephant, or the legs of a crab 

 with the same parts. The vertebrate and invertebrate nervous 

 systems are no more homologous than their skeletons. 



The homology of the spinal chord and the ganglionic chain is 

 opposed, 1st, by the fact that they occupy different positions 

 in the body, — the spinal chord always being enclosed in a 

 bony or cartilaginous canal, the ganglionic chain always in the 

 general cavity among the viscera ; the first being situated in the 



