894 s. H ATT A : 



which is subsequently constricted off from the body-cavity. 

 This takes place at first in the middle region of the body, whence 

 it proceeds both anteriorly and posteriorly. 



Oellacher observed that the Anlage is converted into a 

 longitudinal canal or the segmental duct, being completely shut 

 off from the body-cavity in both the anterior and posterior 

 parts. The anterior section of the duct is much swollen and 

 transformed into the pronephric chamber. From the dorsal 

 aorta, a pair of branches is given off which pushes into the 

 pronephric chamber, pressing against its median wall and giving 

 rise to a pair of the glomeruli. This j^ortion of the duct becomes 

 coiled up and constitutes the pronephros. 



Goette's view somewhat differs from the account given 

 above : the anterior end of the longitudinal groove is not com- 

 pletely closed from the body-cavity, but leaves awhile the com- 

 munication Avith the latter, wdiich is, according to Goette, the 

 morphological equivalent of the nephrostomes of the Amphibian 

 and Petromyzon pronephros. Opposite this nephrostome, he 

 says, the glomerulus is formed by evagination of the visceral 

 peritoneum and projects freely into the body-cavity. This portion 

 of the peritoneum together with the nephrostome is constricted 

 from the rest of the peritoneum ; the coelomic cavity thus shut 

 off is converted into the joronephric chamber. 



This view is essentially confirmed by subsequent writers such 

 as Fuebkinger ('78), Hofemann i^^^), and others, although 

 Hoffmann differs in his view of the mode of the formation of 

 the glomerulus. 



According to the results recently arrived at by Felix'^ in 



1) I know ]iis paper only I)y the iihstract in the Jahreaberichte über die Fortschritte der 

 Analomiexund Physiologie, N.F. Bd. 111. '97. 



