102 FREDERICK TILXEY AND LUTHER F. WARREN 



Differences observed in the cj>i]>hyseal complex in tJic 

 sj)-i< * <>f </<i//o/</s nl /(in/// investigated 



1. Adpenser xtttrio. /v////r////.s-. and rul>icundux. Cattle ('82), 60 

 (ioronowitsch ('88); 153 Garman ('96), and Johnston ('01). ^ 

 The conditions in those forms have been described above. 



2. Lepidoxtcux osseus. Balfour and Parker ('82). 12 Tlie 

 pineal organ in tliis form was first mentioned by these authors 

 ;ind Inter by Sorensen 3 " 3 in 1894, who described the structure as 

 having a distinctly saccular form. 



3. Amia calm. Goronowitsch ('88) 153 and Gage ('93). 135 

 Both of these authors showed that the pineal organ was a simple 

 sac in this species. Hill 180 in 1894 found in the embryonic stages 

 evidences of both parietal organs, namely, what he calls the 

 anterior epiphysis and the posterior epiphysis which probably 

 corresponded to the parapineal and pineal organs in Petromyzon, 

 while the anterior epiphysis is considered the homologue of the 

 parietal eye in Saw' tans. In the later embryonic stages the 

 connection with the brain of the anterior sac is lost. Finally 

 the pineal organ is pushed to the left side. Eycleshymer 112 

 found that the anterior organ has a lumen as late as the 15 to 

 16 nun. embryo. Nerve fibers were observed as late as the 

 12 to 13 mm. embryo going from the commissura habenularis to 

 the interior of the anterior organ. Kingsbury 205 in 1897 observed 

 botli the pineal and parapineal organs in the adult Atnia. The 

 anterior organ was lying to the left of the pineal stalk and was 

 connected with the left habenular ganglion by means of a 

 thick, neural fasciculus. 



4. J'oli/tidon folium. Garman ('90). 143 This species possessed 

 processes which look like nerve fibers. These processes go 

 from the iiitorbrain roof and extend out to an end-sac deeply 

 situated in a parietal fossa of the skull. In one case only was 

 there a complete parietal foramen. 



5. 7W///>/r/-//.s hfchir. Waldschmidt ('87)' 112 



I). I'ali/iiicriix xctH'i/iiliiH. Waldschmidt. 412 Both of these 

 species of ( Yossoptorygii present a pineal organ which has a 

 tubular stalk and rises above the dorsal sac. first upward, then 

 turns sharply forward to end in a slightly dilated end-vesicle. 



