6 NER VO US S YS TEM OF REP TILES A ND BA TRA CHI A NS. 



scope — for all the nuclei of the same animal, a very accurate 

 representation of the actual condition is possible. 



These photographs can now be examined at the library 

 of the Academy of Medicine, the New York Hospital lib- 

 rary. College of Physicians, Philadelphia, Surgeon-General's 

 office and Smithsonian Institute, Washington, and at some 

 university libraries. The same subjects, with over a hun- 

 dred others, printed by the Artotype process on plate 

 paper, showing the structure of the central nervous system 

 of all the North American reptiles, will soon be pub- 

 lished. 



RECAPITULATION OF THE FACTS OBSERVED IN REGARD TO 

 THE SIZE OF THE NUCLEI OF THE NERVE CELLS IN THE 

 SPINAL CORD AND BRAIN OF REPTILES AND FROGS. 



I. FROG. 



Diameters in divisions of Nachet's micrometer eye-piece with 

 objective No. 5 : 



Spinal cord, brachial enlargement 



" crural " 



Centre of motor root of trigeminus. 

 Possible centre of hypoglossus 

 Centre of oculomotorius 



II. EMYS FLORID 



Spinal cord, cervical enlargement 



" lumbar " 



Dorsal region 



Caudal " gradually diminishing 

 Centre of motor root of the trigeminus 

 Cerebellum, large cells 

 Centre of oculomotorius 

 Cerebrum 

 Optic tubercles 



III. — TESTUDO POLYPHEMUS. 



6.5x8. 

 7. XQ. 



6. X6.5 

 4.5 x6. 

 3-5 X4-5 



X6.5 

 xy. 



-4- 



- 2. 



3-5 X 4-5 

 3-5 X 5- 

 3- X3.5 



Same as emys, except in sj)inal cord where the conditions are 

 reversed in the two enlargements. 



