iQog] Trachael Supply, Nervovis System Corydalis 47 



The first to the seventh abdominal gangHa are supphed by one 

 tracheal branch on each side, but these come to the ganglia from 

 a caudal direction because the transverse tracheae in every case 

 cross below or caudal to the ganglion to which they send branches. 

 The transverse tracheae of the abdominal region except the first, 

 are smaller as a rule than those of the thoracic region and the 

 branches which run to the abdominal ganglia are often of consid- 

 erable length. 



The eighth abdominal ganglion is supplied from the outside 

 by two long tracheal branches which come to it from the caudal 

 direction. 



The brain as described by Krauss '84, was found to be sup- 

 plied by three lateral branches on each side from a common trunk. 



The following pages will give a more or less detailed descrip- 

 tion of the tracheal supply in each of the ganglia of Corydalis. 



For the larger branches ordinary dissection under a lens was 

 the method of study. For finer details the entire central nervous 

 system was removed and mounted in glycerine to which a drop of 

 formalin was added. These mounts cleared up in a short time, 

 the air in the finest tracheal tubes remained and they could easily 

 be followed. No sections were studied at this time, but later, a 

 large series of preparations will be examined with several objects 

 in- view, among them the determination if possible of how the 

 finest tracheoles end. 



THE BRAIN. 



The brain is supplied by three main branches on each side, all 

 of which come from a large cephalic tracheal branch. These three 

 seem to be lateral portions from the large common trunk which 

 runs forward somewhat reduced to supply other parts of the 

 head. 



The three trunks on each side, furnish each lateral half with 

 all of its main tracheal branches. (Fig. A and 2.) There are 

 comparatively few tracheae that cross the middle line and most 

 of these are small. These three main portions enter the brain 

 by their branches laterally from the ventral side and the des- 

 cription of them will be gi\-en as though they were seen from the 

 ventral side. 



The most cephalic part is the smallest and the most caudal 

 the largest as a rule. Each part has both superficial and deej) 

 branches, and although the territories of the divisions overlap to 

 some degree, the areas supplied by each are somewhat as follows : 



