766 



tümliche Entwickelung durchgemacht, um dann endlich durch secundäre 

 Rückbildung die primitive Form wieder anzunehmen. In einer künf- 

 tigen Arbeit gedenke ich auf einige auffallende Bauübereinstimmungen 

 zwischen den Nieren der Caecilien und denjenigen eines Amphibium, 

 nämlich Amphiuma, aufmerksam zu machen, welche ebenfalls vom 

 Hauptstamm vor den Differenzirungen des II. bis IV. Typus abzweigten. 

 Die Niere (Urniere) legt sich, wie ich bereits nachgewiesen habe 1 ), 

 wie bei Ichthyophis genau metamer an. 



Paris, 

 Lab. de M. A. Milne-Edwards au Museum, 

 22. Mai 1894. 



Nachdruck verboten. 



On the Presence of a Parapineal Organ in Phrynosoma 



eoronata. 



By Wm. E. Eittee, 



Assistant Professor of Biology, University of California. 



With one figure. 



While studying the pineal eye in the Phrynosoma four years 

 ago, I found, in a single specimen, an accessory vesicle intimately 

 associated with the eye. 



The nature of this vesicle was so doubtful that in publishing 

 the results of my work (Ritter, '91), it seemed best not to describe 

 it until further study should have thrown more light upon it. Such 

 study I have not yet been able to carry out. My efforts to obtain 

 embryos of Phrynosoma have thus far been unavailing; and it was 

 from this source that I had expected the desired light to come. 



However, several recent papers by other workers have furnished 

 facts so strongly and so interestingly suggestive of the significance of 

 the problematical structure which I have observed, that I have thought 

 it best to publish this note upon it. 



I shall first describe the organ, and then point out what, in the 

 light of the papers to which reference has just been made, seems to 

 me a plausible interpretation of its meaning. I apply to it the term 

 parapineal organ used by Studniöka ('93 a) for the accessory vesicle 

 in Petromyzon. It must not, however, be understood that by adopting 



1) Ueber die streng metamere Anlage der Niere bei Amphibien. 

 Verh. der Deutsch, zoolog. Gesellsch., 1892, p. 113—117. 



