THE VICTORIAN NATURALIST. l4? 



Heidelberg. Later researches have discovered a like form in 

 Limncea lessoni and Isidora texturata from the North-Eastern 

 district. The form, however, in the latter cases did not occur 

 alone, but was in company with another form quite distinct from 

 it. That two or more varieties can inhabit the same snail is 

 further testified by the fact that three distinct kinds of cysts have 

 often been found side by side in the same animal. 



And this leads on to the question of cysts, around which has 

 centred the chief interest of the work for the month. Before, 

 however, entering into details as to our local forms, it may be as 

 well to refer to the habit of the embryos of Fasciola hepatica — 

 the fluke of the sheep — as narrated by Professor Thomas in his 

 monograph quoted last month. He says : — "The life of the free- 

 swimming animal never seems to last long, for, on coming in 

 contact with the side of the aquarium or the water plants con- 

 tained in it, the cercaria proceeds to encyst itself. It assumes a 

 rounded form, whilst a mucous substance is poured forth all over 

 the body, together with the granules forming the contents of the 

 cystogenous cells. The whole process of forming the cyst is very 

 rapid, and in a few minutes a layer of considerable thickness is 

 formed, whilst its substance begins to harden." This passage has 

 been quoted to draw attention to modification of habit 

 in the formation of cysts in the Victorian forms of embryo 

 flukes hitherto studied. Most of the encystation seems 

 to take place within the snail. Out of thousands of free- 

 swimming cercarise of different forms, only one or two have been 

 seen to encyst outside the snail, although batches of them have 

 been kept under observation for nearly two days — the length 

 of time they will live in water after removal from the snail. 

 Encystation within the snail, in the case of flukes which reach their 

 final stage in birds, secures easily future development, as the whole 

 snail is swallowed bodily. And the habit presents very little 

 difficulty in cases where the final host is not a snail-eater, since 

 the cysts are doubtless left attached to weeds or grass when the 

 snail crawls over them, having broken through the tissue in the 

 neighbourhood of the liver, which has been rendered soft, and 

 therefore easily broken, by disease. The act of crawling would 

 secure such a result. 



Five different varieties of cysts have been noted. The size 

 and structure of these will be described in a future note. 



Language and Instincts of the Domestic Fowl. — At a 

 recent meeting of the Oxfordshire Natural History Society 

 (England), a lecture was given by Mr. G. J. Burch, M.A., on the 

 language of birds. He explained that he had been led to make 

 a series of systematic observations on the language and instincts 



