Colouring -matters of the so-called Bile of Invertebrates, Sfc. 387 



The haemochromogen in the crayfish and in Pulmonate Mollusca is 

 beyond doubt a respiratory pigment, and it seems to me that in 

 addition to the respiration in the branchia3 of the former and in the 

 pulmonary chamber of the latter, this pigment enables the animal to 

 carry on intestinal respiration, as in certain crabs and Cobitis fossiUs. 

 Semper* refers in a note to intestinal respiration in Mollusca, which 

 from the facts above narrated I believe to be carried on in the 

 intestine of Pulmonates by means of haemochromogen. 



Dr. Sorbyf refers to the importance of the presence of haematin 

 from the standpoint of the evolutionist, so that this question need 

 not be here discussed. 



In addition to the classes of chlorophyll containing animals men- 

 tioned by Geddes, J namely, those which vegetate by their own intrinsic 

 chlorophyll and those which vegetate " by proxy," so to speak, or by 

 means of parasitic algae, a third class must now be added : those 

 which contain enterochlorophyll in their livers, or other appendages 

 of the enteron. 



Conclusions. 



(1.) The existence of enterochlorophyll in the liver, or other 

 appendages of the enteron in Invertebrata, is definitely established. 



(2.) This pigment occurs in greatest abundance in Mollusca, it 

 occurs less frequently in Arthropoda, and its presence among Vermes 

 is not proved. 



(3.) The pyloric cceca of starfishes contain it in abundance, also 

 the intestinal appendage of Echinus, which fact shows that the former 

 function like the so-called liver of other Invertebrates. 



(4.) The bile of the crayfish and that of Pulmonate Mollusca con- 

 tains haemochromogen ; in the latter it is generally accompanied by 

 enterochlorophyll, and appears to be concerned more in aerial than 

 aquatic respiration. 



(5.) The so-called liver of Invertebrates is a pigment producing 

 and storing organ, as well as being concerned in the preparation of a 

 digestive ferment. 



(6.) The presence of haemochromogen in the bile of Invertebrates is 

 apparently determined by their mode of living ; for instance, it is not 

 distributed according to purely morphological considerations. 



(7.) It is not impossible that the chlorophyll referred to may be 

 synthetically formed in the animal's body, but any conclusion of this 

 kind is premature at present ; although all the facts observed tend to 

 support this view. 



* " Animals and their Conditions of Existence," " Internat. Sci. Series," vol. xxxi, 

 note 71 to page 171. Cf . also Darwin's " Origin of Species." 

 f " Evolution of Haemoglobin," loc. cit. 

 X Loc. cit. 



2 c 2 



