NERVUS TERMINALIS TN AMIA 77 



beyond the cranial cavity to reach the nasal capsule, but this 

 last point could not be determined with certainty from the prepa- 

 ration. 



However, the main blood supply to the nasal capsules is de- 

 rived from the external carotid artery. The branch which sup- 

 plies each nasal capsule joins the olfactory nerve just anterior 

 to the main mass of the ganglion of the nervus terminalis. This 

 position of the artery with reference to the ganglion was found 

 to be true for all stages of development subsequent to the ap- 

 pearance of the ganglion. The artery approaches the nerve from 

 the ectal side and circles ventrally beneath it to come into close 

 proximity with the ganglion. The artery divides as it runs for- 

 ward and its branches passing near the scattered cells of the 

 nervus terminalis, turn dorsad with the fibers of the olfactory 

 nerve until they reach the basement membrane of the nasal 

 epithelium lying along the mid-rib. From this point the arteri- 

 oles turn laterally right and left, along each secondary fold of 

 the Schneiderian membrane. An occasional nerve cell lies 

 slightly dorsal of the olfactory nerve, but for the most part, the 

 cells are located, as indicated in fig. 9, between the two main 

 rami. 



ADULT STRUCTURE OF THE OLFACTORY ORGAN IN AMIA 



Amia lives much in swamps and Reighard ('03) has shown that 

 when an adult is released from a boat it quickly buries itself in 

 the slime at the bottom. The distensible nasal tube has a very 

 small aperture which would be of advantage in filtering the 

 water taken into the nasal capsules (fig. 13). The size of the 

 nasal capsules, which almost equals that of a shark of the same 

 size, indicate that Amia is macrosmatic as compared with other 

 fishes. There are in the adults from fifty to seventy secondary 

 folds on either side of the mid-rib of each nasal capsule (fig. 13). 



Some experiments were made to determine how the water 

 circulates in the nasal capsule. When colored fruit juice was 

 introduced by means of a long pipette into the water of an aqua- 

 rium containing a living adult, the nasal tube (fig. 13) inhaled 



