THE PINEAL BODY 



97 



of the interbrain. There is a small conical, proximal portion. 

 Cattie 60 states that the parietal foramen is closed only by the 

 dura mater. 



RAIIDAE 



1. Raia clavata. Ehlers (78) ; 108 Cattie ('82). 6 In this spe- 

 cies a thin, long stalk extends far forward and terminates in a 

 definite end- vesicle which is enclosed in a deep prefrontal fossa. 



/'/" /' Os C/f 



Fig. 50 The pineal region of Torpedo ocellata, according to d'Erchia, 1896. 



Hm., hemisphere; Pf , paraphysis; V., velum transver um; Ds., dorsal sac; 

 Ch., commissura habenularis ; S h , pars intercalaris posterior; Cp., posterior com- 

 missure; M., midbrain 



2. Raia follonica. Studnicka ('95). 385 The pineal organ here 

 is found as a thick stalk with a lumen. There is no special 

 proximal portion. In the lumen there is a syncytium. 



3. Myliobatis aquila. Studnicka ('95). 385 In this form, as 

 in Raia clavata, the stalk is tubular and reaches from the inter- 

 brain to the roof of the skull. The end-vesicle is dorsoventrally 

 flattened and rests in the region of the prefrontal fossa, which 

 latter shows but a slight deepening in the skull. 



4. Torpedo marmorata. Studnicka ('95). 385 In this form the 

 pineal organ fails to appear, although there are present two 

 well-developed ganglia habenulae. 



MEMOIR NO. 



