39G s. HATTA : 



cess proceeds posteriorly until the duct comes to lie close to the 

 rectum (Enddarm). 



Felix thus observed the segmental Anlage of the pronephros 

 in its glandular part, and derives the rest of the system from 

 the proximal margin of both tlie parietal and visceral layers of 

 tlie secondary lateral plate ; he has observed neither the posterior 

 growth, nor the epiblastic origin, of the segmental duct. 



The pronephric chamber which results from the confluence of 

 the five pronephric tubules, is not homologous, according to 

 Felix, with that of Amphibia, in which the chamber should be 

 a constricted part of the body-cavity into which the tubules 

 open. 



Quite recently, 8\vaen and Brächet ('99) have published a 

 paper on the early development of the mesoblastic organs in 

 Salamonidœ. Although my manuscripts were nearly finished, 

 when I saw this interesting paper, I must here refer in a few 

 words to it^\ 



The authors found the first traces of the pronephros under 

 the fifth somite, of two embryos, one of which was in the stage of 

 11 somites, and the other of 13 somites. It is not the product 

 of the parietal layer of the lateral plate only, but is formed, 

 as Felix believes, by the proximal portion of both the parietal 

 and visceral layers of the secondary lateral plate (l'extremé interne 

 de la plaque latérale secondaire"^). The internal cavity enclosed 

 by the pronephros is, therefore, not the diverticulum, but a 

 part of the body-cavity. 



1)1 am much indebted to my fiieiid, Dr. A. Oka, who read the paper iV)r uie- 

 2)Accordhig to the authors, the " plaque hiterale primitive " is divided into the "plaque 



latérale secondaire" and llic "masse intermédiaire;" tlierefoie, the "plaque latérale 



secondaire" corresponds to the hiteral plate \t6L'\t' oi' Pel rum i/zon. 



