Mr. n. J. Carter on the Organi::ation of Infusoria. 125 



That these cells in Planaria and Otostoma are homologous 

 organs can hardly be doubted, both from their general characters 

 and their corres})ondence in position ; but what their office may 

 be is at present unknown. Occurring, however, as they do, in 

 the stomach of Planaria and Rotifera, where there is no other 

 analogue of the so-called biliary follicles of the lower worms*, 

 and being almost identical in Otostoma and Planaria, they not 

 only ally these two organisms, but, at the same time, appear to. 

 be the homologue of the biliary follicles in each. ;i« 



I have never seen any cells of this kind in Amoeba, unless the 

 ''granules^' already described be their analogues. It appears 

 evident that these are the same both in Amoeba and the sponge- 

 cell, and that they are the seat of the green colour in the latter. 

 Are the green granules of the sponge-cell analogous to the parts 

 or cells respectively which hold the colouring matter or endo- 

 chrome in the Diatomeee, Closterium, Spirogyra, Cladophora, &c., 

 and (through the latter) to the "green disks" or peripheral 

 layer of chlorophyll-bearing cellules in the internode of Nitella, 

 and those which, scattered irregularly through its moving pro- 

 toplasm, are circulated round the cell of Serpicula verticillata 

 (figs. 63 a, 64 a) ? If so, the chlorophyll-bearing parts of the 

 protoplasm in vegetables may be the analogue of the liver in 

 animals. In some Rotifera the spherical cells appear to bear 

 bile as green as grass or chlorophyllt^ while in others it is 

 yellow. The same diversity of colour occasionally manifests 

 itself in the Diatomea ; while in Spirogfjra especially, the oil- 

 globules and amylaceous dej)osits, which abound in abortive 

 conjugation, are entirely confined to the green spiral-bands, thus 

 corresponding, in one identically, and in the other transitionally, 

 with the fat and sugar which are formed in the liver of man ; the 

 colouring matter in all of course being, when present, a mere 

 indication cat. par. of the nature of the organ. How the colour- 

 bearing cellulse of the spherical cells are produced in Otostoma 



* By this I do not Mean to class the Planarians with the Worms. Mr. 

 C Girard, who has followed out the " Embryonic Development of Flano- 

 cera elliptica," would ally them to the Gasteropoda, — * Researches upon 

 Nemerteans and Planarians/ 4to, Philadelphia, 1854. 



t Since writing this, 1 have seen Diglena catelUna, Ehr., discharge the 

 green matter from its alimentary canal, and retain nothing but the ordinarily 

 coloured biliary cells ; also D. cauduta to have the whole of the soft tissues 

 of its body coloured in this way, unless there be diverticulations of the 

 stomach to this extent ; so that I now begin to think this colour, which at 

 first a])pcared persistent, to be adventitious, and gained from the Euglenee, 

 and, perhaps, chlorophyll-bearing protoplasm on which these species chiefly 

 feed. Accidentally, perhaps, the bile may become green in any species of 

 Rotifera, as in animals generally ; and this appears to be the case with the 

 endochrome of Diatomeee. 



