154 FREDEKICK TILNEY AND LUTHER F. WARREN 



Klinckowstroem 206 in 1892 has shown in certain aquatic birds 

 during embryonic stages, a very early appearing, peculiarly 

 pigmented spot on the head. This he found in twelve out of 

 two hundred embryos of Sterna hirundo, Larus canus, Larus 

 marinus, Larus glaucus, and Anser brachyrhynchus. In adults 

 of these forms no such spot exists. There is little evidence to 

 indicate the tendency to the formation of a parietal foramen. 



Dexter ('02) 90 observed in Gallus domesticus that the para- 

 physis is an appendix of the paraphyseal arch, developed from 

 the brain wall. He believes it to be glandular in character. 

 In the adult of this form it is composed of a modified ectodermic 

 tissue. In the younger stages its walls are thin and its cavity 

 is large, but in the adult chicken or hen the reverse is true. It is 

 oval in shape and lies nearly parallel with the longitudinal axis 

 of the cavity of the forebrain. It is a constant structure, and 

 Dexter has identified it time and again in the embryo, in the 

 chicken, and finally in the full-grown fowl. Its position is very 

 characteristic. The paraphysis is situated immediately dorsad 

 to the foramen of Munro and anterior to the prominent fold of 

 the chorioid plexus which must morphologically correspond to 

 the velum transversum. 



Differences observed in the epiphyseal complex in the various 

 species of birds already investigated. 



1. Gallus domesticus. Stieda ('69) ; 376 Dexter ('02) ; 90 Galeotti 

 ('96). 14 It was observed in this form that the epiphysis is 

 follicular in structure and glandular in character. 



2. Meleagris gallopavo. Mihalkovicz ('77) 275 observed that 

 the epiphysis is follicular in this form. 



3. Sterna hirundo. Klinckowstroem ('92) 206 found remains of 

 the parietal spot in the embryo. 



4. Anas domesticata. Klinckowstroem ('92). 206 In this form 

 the author observed that the epiphysis is follicular. 



5. Apteryz. Parker ('92). 301 The epiphysis in this form is 

 usually anteflexed, although in some instances it is dorsiflexed. 



6. Perdix cinerea. Studnicka (96). 386 The epiphysis in this 

 species is follicular. 



7. Strix flammea. Studnicka ('96). 386 In this form the epi- 

 physis is partly solid and partly follicular. 



