M. Nicolucci on the Anatomy of the Triton aquaticus. 291 



Comparetti are visible, which appear to penetrate as far as the 

 auditory organ, and which are again met with under the skin, 

 of the use of which we are ignorant. Certainly thc}^ cannot 

 be confounded with the dermal follicles which secrete the 

 mucus with which the surface of the Salamander is covered, 

 as they are considerably larger than these and quite different 

 in colour. 



The spinal marrow has not any enlargement corresponding 

 with the nervous plexuses, which are directed to the anterior 

 and posterior extremities ; but the nervous filaments which 

 spring from it have only a double root, which appears evi- 

 dently in all the costal nerves, resembling Avhat Delle Chiaje 

 has observed in the Proteus. The brachial plexus is formed 

 by three cervical nei'ves, which send off, before they unite, 

 filaments both for the skin and the surrounding muscles, and, 

 again united, divide into two branches, of which the shorter 

 radial does not go so far as the fore-arm, dividing itself 

 into infinite ramusculi ; and the cubital, having furnished 

 branches to the muscles of the arm, parts into four digital 

 branches, each directed to its own finger. The plexus ischia- 

 ticus also consists of three lumbar nerves, of which the 

 median sends branches to the genital organs and to the 

 kidneys, the posterior sends small filaments to the neigh- 

 bouring muscles, and the superior join to form two trunks, 

 the anterior and posterior sciatic ; the first the shorter, which 

 does not reach so far as the thigh ; the second, which extends 

 to the foot, parting into two branches, one which supplies the 

 two digital nerves to the first two fingers, and the other those 

 of the remaining three. 



The great sympathic nerve appears to have its origin from 

 the third cervical nerve, from which a filament is seen to be 

 given off", which, passing across the other cervical nerves that 

 form the brachial plexus, gives origin to the exceedingly mi- 

 nute ganglions on the spinal nerves precisely where their double 

 roots join, and terminates in the first of the lumbar nerves, 

 which unites with the others in forming the plexus ischia- 

 ticus. 



The cerebral nerves of the Salamander are reduced to the 

 first, second, fifth, eighth and ninth pairs. The first of these 

 or the olfactory, springing from the anterior part of the cere- 

 bral hemispheres, immediately distributes itself in the nasal 

 cavity ; the second or the optic, springing from the rudimental 

 optic thalami ? (lobes), turns towards the eye, the bulb of which 

 it penetrates entire ; and the fifth or the trigeminus, taking its 

 rise immediately in the upper part of the medulla oblongata, 

 trifurcates after having given origin to a ganglion, the first 

 U2 



