392 MARION I. NEWBIGIN. 



Preliminary. 



The existence in various Invertebrates of pigments present- 

 ing a remarkable resemblance to chlorophyll has long been 

 known. Of these pigments the most familiar are the green 

 pigments of the worms Bonellia and Chsetopterus, and 

 the pigment described by Dr. MacMunn as enterochlorophyll. 

 In each case an identity with chlorophyll has been asserted by 

 different authors. The green pigment of Bonellia has been 

 described as chlorophyll by Schmarda, Schenk, and others^ 

 although the researches of Sorby, Geddes, and Krukeuberg 

 long ago demonstrated the erroneous nature of the description. 

 Similarly, Professor E. Ray Lankester, who discovered the 

 peculiar pigment of Chsetop terus, called it a "chloro- 

 phylloid^^ substance, and at one time placed Chsetopterus 

 in the list of chlorophyll-containing animals, although he no 

 longer maintains this position. In the case of "entero- 

 chlorophyll,^^ however, Dr. MacMunn's application of the term 

 chlorophyll has not been seriously challenged. 



During some work on the pigments of the Crustacea I 

 came across a statement by Dr. MacMunn that enterochloro- 

 phyll occurs at least in some cases in the "liver^^ of these 

 forms. Not being able to find it there readily, I resolved to 

 study its properties in the organs in which it was first de- 

 scribed, namely, the digestive glands of the MoUusca. Soon 

 after I had begun this work Professor Lankester sent me 

 some solutions of the pigments chsetopterin and bonellin, and 

 asked me to make a chemical examination of them. I found 

 so much resemblance between the chaetopterin solutions and 

 solutions of enterochlorophyll as to make it desirable to study 

 the two pigments side by side. In the interim Professor 

 Lankester's own paper on chaetopterin appeared, with spectro- 

 scopic observations by Drs. Beuham and Engelmann. 



I am much indebted to Professor Lankester for the solutions 

 of chaetopterin and bonellin which he sent, to Professor W. A. 



