252 ANIMAL PARASITES. 



organ in our Distomum young individuals, sexually immature, 

 are the best adapted, and especially those whose intestine con- 

 tains little or hardly any bile. In these we clearly see light, 

 contorted canaliculi, branched towards the margins, collecting 

 in the middle into a straight sac, which is dilated in the form 

 of a bell near its extremity. In adult individuals the sys- 

 tem in question becomes more distinct when the intestine is 

 emptied, and the Distomum has been kept for some time in bile or 

 water. It forms an immense number of small branches, which 

 penetrate into the furthest portions of the body, sometimes collect 

 into larger stems, and pass into a tolerably strong terminal stem, 

 which runs in the median line of the hinder portion of the animal, 

 and becomes dilated and bell-shaped at the extremity of the body, 

 where it opens occasionally, and gives issue to molecular contents, 

 mixed with larger, lighter bodies. I could not discover any 

 sphincter muscle at this part of the end of the body. As re- 

 gards the contents of this whole system, they are characterised 

 by their limpid colour, and by small, diaphanous globules, 

 such as we find in all Trematoda. By direct light these bodies 

 shine out of the vessels with a chalky white colour. According 

 to Von Siebold and most authors, these bodies, which possess a 

 tolerably firm consistence, are regarded as calcareous corpuscles, 

 analogous to the well-known calcareous corpuscles of the Cestodea. 

 I have not succeeded in effecting the destruction of these bodies 

 in Dist. hepaticum with acetic acid so rapidly as in the Cestodea, 

 nor have I observed a similar evolution of bubbles of carbonic 

 acid. It is therefore by no means clear to me whether these 

 globules are to be regarded as carbonate of lime, or whether they 

 may not perhaps be earthy salts of another weak acid, which dis- 

 solve slowly, and without evolution of gas, under the action of 

 acetic acid. Many of these corpuscles may, perhaps, also belong 

 to the masses which we denominate Barcode. For my part, there- 

 fore, I believe that the true nature of these structures has not yet 

 been ascertained, however many of our first authorities upon this 

 subject may regard the affair as settled. 



by Aubert. It is only to be regretted that in the explanation of the figure on p. 374 K, 

 we read "Origin (Ursprung] of the water-vascular system from the excretory organ." 

 The word origin (Ursprung} is adapted only to produce confusion as to the nature of 

 the organ. It would be much better, and more suited to the description given, if we 

 read instead " Point of transition (Uelergangsstelle) of the water-vascular system into 

 the part of the system which has hitherto been called the excretory organ." 



