6 Hans Gadow, 



area of tlie disteiidiiig' ocellus becomes lighter and witliin it appears 

 a pigment whicli may vaiy from warm brown to bright red; the 

 areas of tlie ocelli become the red bands and all that remains of 

 the xantliic ground colour appears now in the shape of the yellow, 

 or white, interstitial rings, bordered by black in front and behind. 



It is important to note that in this series a unit is composed 

 of one red band, one anterior and one posterior black ring (the remnants 

 of the black rim of the original ocellus. A complete segment 

 containing all the three colours is in this DM. series composed of 

 Black -j- Red + Black — Yellow (or in the reverse order), whilst in 

 the SE. series the seqnence is Red — Yellow + Black -\- Yellow (or 

 in the reverse order). 



Fnrther changes. In the DM. series the Y^ellow or light ground- 

 colour holds its own; it may often be purified into bright yellow, 

 occasionally into white in correlation with mineral deposits, but it 

 is not invaded by melanine. There are however tvvo black rings to 

 every red one in each unit, and black pigment stronglj^ tends to 

 become the dominant colour within its morphological unit. When 

 this happens, increase of the black results in the encroachment 

 upon the red until this is reduced to small patches or even vanishes 

 completely; cf DM. 5. The respective segment is then composed of 

 one long black band and one narrow yellow ring. 



If this conversion of the red fields or bands happens to every 

 segment the whole snake will be black, with narrow yellow rings, 

 eg. Coronella micropJiolis var. F. in Boulenger's Cat. Snakes Brit. 

 Mus., the tail of Elaps euryxantJms, and often of ^. fulvms. But most 

 specimens retain some of the red bands intact, sometimes alternating 

 so that two red bands are separated by five other rings and bands, 

 namely two yellow and three black of which the middle one is the 

 broadest. The most interesting stages are of course those in which 

 the conversion of the red bands is arrested, so to speak in a lopsided 

 manner, as if there were some constitutional obstacle; cf. the 

 specimen of Coronella micropholis collected hj myself at Carrizal, 

 West of the lower ßalsas river in Michoacan, and the specimen of 

 Elaps fulvius found by myself at the JoruUo Volcano. This regularly 

 alternating suppression and preservation of the red bands is exactly 

 repeated by E/aps surinamensis (see Jan, pt. 42, tab. 6), or in specimens 

 of E. niarcgravi. 



An interesting but simple departure from any of the above 

 stages is the change of yellow into red rings, so that the paired 



