76 P RATHER. [VOL. I. 



zung der einzelnen Theile dieser Region gelang mir erst unter 

 vergleichender Priifung nahe auf einander folgender alterer 

 Stadien." 



I likewise believe that Kupffer has misinterpreted what he 

 saw, but for an entirely different reason from that given by 

 Haller, yet based upon the same passage. 



Miss Phelps 1 has recently shown that the "larval adhesive 

 organ " in Amia develops at about the time that Kupffer assigns 

 to the formation of the hypophysis in Acipenser. The adhe- 

 sive organ begins as a cliverticulum from the endoderm anterior 

 to the brain, which later becomes divided into a pair of diver- 

 ticula whose connection with the endoderm becomes broken off 

 after a time. Acipenser and Lepidosteus each possesses a 

 sucking disc, or adhesive organ, similar to that in Amia and 

 at a corresponding developmental period. It would therefore 

 seem that they should justly be regarded as homologous organs, 

 and, further, we should naturally expect them to have a similar 

 ontogeny. Previous to the observations of Miss Phelps this 

 organ has been assumed to be of ectodermic origin (Dean for 

 Amia, Balfour and Parker for Lepidosteus, and Kupffer for 

 Acipenser). 



In my own studies on Amia, as described on a preceding 

 page, I observed these diverticula connecting the foregut with 

 lateral masses of cells lying on either side of the snout and 

 between the anterior end of the brain and the overlying epi- 

 dermis, filling nearly the whole of this pre-cerebral region. 

 These masses of cells present an appearance exactly like the 

 cells walling the foregut, being laden with much yolk just as 

 Kupffer describes, and could not be distinguished from them. 

 The narrow channels can be traced from the cavity of the fore- 

 gut upwards through the masses to near the epidermis on the 

 dorsal side where they end blindly. The cells of the epidermis 

 and brain contiguous to these present a very different appear- 

 ance, due to their freedom from yolk. 



I was at a loss to account for these canals connecting the 

 enteric cavity with organs on the dorsal side of the head, until 



1 "On the Development of the Larval Adhesive Organ in Amia." Abstract in 

 Science. March 10, 1899. 



