the Syngamus trachealis. 255 



great ravages on the feathered tribe, that their owners have 

 been obliged to have recourse to a remedy for it. 



The worm consists of an extended cylindrical body, divided 

 towards the upper part into two long branches: the two 

 branches vary in thickness. The thickest branch forms pro- 

 perly the anterior extremity of the body, and if we reckon 

 it to the whole length of the body, the other and more slender 

 branch extends from the junction of the middle and anterior 

 third of the body, making an acute angle with the anterior 

 extremity. The whole length of the body is nearly half an 

 inch, its thickness towards the hinder part 4 to J lin., the 

 thirmer branch is 1^ lin. in length and measures about ^ lin. 

 in diameter. In order to distinguish better the two branches, 

 I shall call the thick one the female branch and the thinner the 

 male branch, which I hope toprove in the course of this memoir. 

 The male branch is sometimes shorter, sometimes longer than 

 the female branch. The motions of this animal are very slow. 

 Its colour is brick-red, and equals in brightness that of the 

 lungs of birds ; at both heads the red passes into yellow. The 

 whole worm is transparent, and the red-brown intestine and 

 the convoluted generative organs are visible through its integu- 

 ment. If the worm be kept for some time in water, the red 

 colour disappears and a dirty yellow takes its place ,* the co- 

 lour of the male branch is always fainter than that of the body. 

 The heads of both branches are of the same structure, only that 

 of the male is inferior in thickness to that of the female. The 

 description of one branch may therefore suffice for both. I 

 found the worm at times with the head of one of the branches, 

 at times with the other, fixed to the mucous membrane of the 

 windpipe. This cephalic extremity, the upper free end of both 

 branches, is always inflated, and is contracted at the place 

 where the head, which by this operation has taken the form 

 of a ball, passes into the branch : exactly in the middle of the 

 head is a round wide aperture or mouth. The female branch 

 is very little bent; the male, on the contrary, has often the 

 form of an S or winds round the female branch. At the place 

 where both branches join is perceived, in the obtuse angle 

 which the male branch makes with the body, a slit-like aper- 

 ture or fissure (see Plate I. fig. 6. c), out of which I have seen 

 the eggs glide, and in which therefore we have to look for the 

 vulva. The body is bent down to its most inferior part in a 

 soft undulate form, and at its end is round and truncated; 

 from the middle of this blunt end of the body descend some- 

 times shorter sometimes longer arms or stalks. An anus was 

 nowhere to be found. 



On examining the interior part of this animal, I found as 

 follows: The exterior skin surrounds, 'as \n xhe Nematoidea^ 



