242 PSEUDO-HELMINTHS. 



the readers of this Journal in July, I ought to say, perhaps, that 

 my task was a simple one — that of verification, or, more properly 

 speaking, classification. But a professional friend and naturalist 

 tempts me into a byepath of speculation. He insinuatingly 

 writes : — " Would it not find a more fitting place among Nema- 

 TODA, and probably be Filaria bronchialis ? " My reply is that it 

 certainly belongs to the Treisiatoda, although it bears a close 

 resemblance to the male Sderostoma syngatnus, a nematode ento- 

 zoon, better known under the name of the Gape-worm, a parasite 

 not only more widely distributed, but is invested with a special 

 general interest from the fact that it is the cause of the gape- 

 disease among chickens, pheasants, partridges, magpies, hooded 

 crows, starlings, swifts, and many other birds. There is an 

 undoubted family likeness, however, among the embryos of all 

 the genera of entozoa. The first stage of their existence and 

 development is passed in the water and as free swimmers, quite 

 irrespective of whether their final destination be Redice or 

 Cercarice. 



In the cause of suffering humanity, it is quite worth while to 

 pursue the morphology of these pests somewhat further. There 

 is yet so much to learn regarding them and their several stages of 

 existence, the more intimate relations which obtain between their 

 embryos and their intermediary hosts, and the extent of the 

 pathological conditions to which they sooner or later give rise in 

 the animal body. We are quite unable to guess by what instinc- 

 tive agency they are enabled to discover and select the most 

 appropriate resting-place in the interior of this or that animal, and 

 whereby they are enabled to attain to a higher state of organisa- 

 tion. Nothing can strike us with more astonishment than that 

 the Gape-worm, Sderostoma synganms, should select and find its 

 way, not to the oesophagus, but to the windpipe of the chicken or 

 bird, and thus subject its host to a cruel death by suffocation. It 

 seems to be bent upon propagating its species at the cost of life 

 to the higher orders of creation. With reference to internal para- 

 sites as a whole, although certain districts are known to have 

 special attractions for many of them, yet none seem to have an 

 abiding resting-place. On the contrary, all have a disposition to 

 roam over a wide area, and it is in this way they so thoroughly 



