CETACEA 



419 



Distoma and the branched tubes seen in Fasciola. This led 

 me originally to place the worms in a distinct genus (Campula). 

 Perhaps there were no sufficient grounds 

 for this generic separation ; but in all 

 Dr Anderson's specimens obtained from 

 the liver-ducts of the Gangetic dolphin 

 more or less decomposition of the con- 

 tents of the intestinal tubes had occur- 

 red, consequently the angular appearance 

 of the folds is entirely lost. From the 

 other characters presented by the worms 

 I believe that these flukes from the 

 Ganges are specifically identical with 

 those originally obtained from the por- 

 poise of the Firth of Forth. For 

 reasons elsewhere stated at full length 

 I have merged my genus Campula into 

 that of Distoma. Thus, Campula ob- 

 longa is a synonym only. I cannot 

 here treat of the morphology of trema- 

 tode organisation as it deserves ; but 

 in relation to the question of transition- 

 forms I may remark in passing that an 

 extreme degree of intestinal folding 

 seems as if it must result in branching. 

 This, I think, would happen should any 

 departure from the central distome type 

 be rendered necessary by the exigences FJQ 68 _ Distl 

 of the creature. At all events, the 

 spirally-twisted and branched digestive organs constitute diffe- 

 rent ways in which nature attains one and the same end. 

 I may add that this coiled condition of the tubes in D. 

 Campula is by no means unique, since I have seen it in 

 other trernatode forms, as, for example, in my D. compactum 

 from the Indian ichneumon. Dr Anderson's specimens of 

 D. Campula furnish a good general view of the reproductive 

 organs. They show that the single, relatively narrow, and 

 unbranched uterine canal is of great length, and coiled upon 

 itself in a very tortuous manner. In this way the duct passes 

 from side to side, crossing the central line of the body at least 

 a dozen times, whilst every fold is likewise bent upon itself to 

 such an extent as to increase its length to at least four times 



original. 



