454 SIMON H. GAGE 
adult Petromyzon, in some teleosts Ameiurus, and may be found 
in the retinae of higher forms when sufficiently -investigated. 
Fortunately Bermuda has also in its waters the little Amphi- 
oxus discovered by Andrews in the Bahamas (Asymmetron 
lucayanum). Asymmetron showed also glycogen in the nerve 
cells, agreeing in every particular with Amphioxus. Through 
the courtesy of The Wistar Institute, I was enabled to examine 
Amphioxus from Naples also, and found glycogen in even greater 
abundance if possible in its nerve cells. Probably glycogen is 
present in the nerve cells of Amphioxus wherever found. 
GLYCOGEN IN THE CENTRAL NERVOUS SYSTEM AND RETINA OF 
THE LAKE LAMPHREY (PETROMYZON MARINUS UNICOLOR), 
AND THE BROOK LAMPREY (LAMPETRA WILDERI) OF 
THE CAYUGA LAKE BASIN 
After finding glycogen in the nerve cells of Amphioxus it 
seemed probable—at least not improbable—that it might be 
found in the nervous system of Ammocoetes (larval Petromyzon 
and Lampetra), whose life habits are so similar to Amphioxus, 
although living only in fresh water. On returning to Ithaca 
from Bermuda, larval lampreys of all sizes were obtained in 
nature and put directly into 95 per cent alcohol and some also 
in absolute alcohol, exactly as had been done for Amphioxus. 
On sectioning and staining this material, glycogen was found as 
hoped, and it was in brain cells as well as in those of the myel 
(medulla spinalis). Not all nerve cells contain glycogen, but 
many of them. In the larval Petromyzon (Ammocoetes) there 
was another striking fact brought out in the sections: The 
tissue surrounding the central nervous system has the general 
appearance of fat; with the glycogen stain almost every cell 
showed abundant glycogen in a part of the cell. On using Sudan 
III, and osmic acid, as well as the glycogen stain, it appeared 
that the cells in the loose tissue enclosing the central nervous 
system were most of them filled in part with fat and in part with 
glycogen. The cells in the dorsal region of the abdomen around 
the mesonephros and gonads were also in many cases partly 
surrounded by similar cells filled with fat and with glycogen. 
