FROM THE DOLPHINS OF THE GAIfGES. 41 



wlien pushed furtlier, result in branching. This, I think, would 

 happen should any departure from the central distome type be 

 rendered necessary by the exigences of the creature. At all 

 events, the spirally twisted and branched digestive organs consti- 

 tute different 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 imique, since I have seen it slightly developed in 

 other trematode forms, and very conspicuously so in a species 

 (-D, compactum) which I procured from an Indian Ichneumon, 

 described to this Society in 1859. 



Turning to the other internal organs, I have to state that whilst 

 the flukes from the Porpoise only showed that the vitelligene 

 glands were well developed and that the reproductive outlets occu- 

 pied the usual position. Dr. Anderson's specimens have furnished 

 a good general view of all the reproductive organs. In particular 

 they show that the single, relatively narrow, and unbranched 

 uterine canal is of great length and coiled upon itself in a singularly 

 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 that of the animal. In short, the 

 uterine folds may be pretty accurately described as passing in a 

 regular manner from side to side, each separate coil being very 

 much twisted upon itself, thus frequently forming secondary coils. 

 In the fluke here drawn (PI. X. fig. 2) I have accurately represented 

 every winding of the duct from its vaginal outlet above to its ter- 

 mination, where it is joined by the ovarian and vitelligene ducts 

 in the ordinary way. Only the merest traces of these smaller 

 channels, however, were here and there visible ; but the two oval 

 testes are conspicuous and well defined, occupying a position 

 somewhat lower than usual in the typical forms of fluke. There 

 was a third organ, apparently the ovary. This was less well de- 

 fined, and situated higher up in the middle line. The vitelligene 

 glands occupied the usual position ; but their precise limits could 

 not be accurately fixed throughout. The terminal cells or cap- 

 sules with their efferent ducts were well seen in several specimens. 

 Lastly, the water- vascular system was constantly visible, ' or at 

 least that part of the main channel which expands into a large 

 vesicle immediately above the central point of the tail. At this 

 part several of Dr. Anderson's specimens had given way entirely, 

 the parenchyma of the body, and sometimes the testes, bursting 



LTSS. .TOTTBIf. — ZOOLOGT, VOL. XTII. 4 



