522 p. E. SMITH 



double epiphysis, but does not indicate why one should arise 

 earlier than the other as has been demonstrated to be the case by 

 Eycleshymer and Davis ('97) and others. 



In amphibia the epiphysis is small. With one exception (Cam- 

 eron '03) the latter organ has been described as a single diver- 

 ticulum: De Graaf ('86) and Blanc ('00) in Triton; Leydig (53), 

 Burckhardt ('91), Galeotti ('97) in Salamandra maculata and S. 

 perspicillata; Orr ('89) in Amblystoma mexicanum; Eycleshymer 

 ('92, '95) in A. punctatum; Mrs. Gage ('93) in Diemyctylus; 

 Kinsgbury ('95) and Warren ('05) in Necturus. Cameron ('03) 

 in a brief paper, with no description or figures, stated that in 

 certain amphibia (Rana, Bufo, Triton) the epiphysis arises as 

 two primary outgrowths, these being placed one on each side of 

 the mesial plane. 



Warren ('05) suggests that there is some sort of a proportion 

 in the relative development of the paraphysis, epiphysis, and 

 parietal eye, for in urodela, where there is no parietal eye, and a 

 small epiphysis, the paraphysis reaches its maximum develop- 

 ment. Certainly in amphibia the paraphysis is much larger than 

 in the higher or lower forms. That the epiphysis is correspond- 

 ingly small might suggest a phylogenetic vicarious action between 

 the two structures. 



Reptilia have been a favorite field for work on the epiphysis and 

 pineal eye. In most reptilia the epiphysis is at first double, the 

 anterior vesicle then becomes constricted, migrates forward, lodges 

 in a foramen iii the skull, and is known as the parietal eye. In 

 certain forms, however, the epiphysis has been described as 

 lacking: Sorensen ('93, '94) and Reese ('10) in the alHgator, and 

 Voeltzkow ('03) in the crocodile and caiman. 



In Desmognathus the paraphysial arch and paraphysis have 

 nothing distinctive. The two paraphysial evaginations were found 

 in all the series examined. The posterior evagination continues 

 to grow, absorbing the anterior one and becoming the paraphysis 

 of the adult. 



The epiphysis forms in the caudal portion of the second dience- 

 phalic neuromere, just cephalad to where the posterior commis- 

 sure appears. In Desmognathus it appears earlier than the 



