108 CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 



emerge ouly at the death of the latter. Cuticle, with very delicate 

 striae, disappearing with age, but persisting- in the cervical region. 



Are there several species of Syngamus ? Up to the present time hel - 

 niinthologists have agreed to admit but a single species, the Syngamus 

 trachealis of Siebold ; but the characters which they attribute to it differ 

 in certain points from those of the species which we have studied as in- 

 festing the pheasants in France. Thus the latter attains twice the 

 dimensions given by Dujardin. The head of the male, says this ob- 

 server, is obliquely truncated, while in the species examined by us it 

 is squarely terminal. The tail of the female, Dujardin continues, is an 

 elongated cone and the anus 1.2""™ (.047 inch) from the extremity, 

 while in the parasite of our pheasants the tail is either abruptly conical | 

 or rounded like a stump and pointed ; in other words, it has the form 

 of a cylindroconical appendage, springing from the middle of the 

 rounded posterior extremity (Plate I, Fig. 3) 5 the anus opens at the 

 base of this small tail, which is not more than .1 to .2'"™ (.004 to .008 

 inches) long. 



Unless there was some error of observation, or some typographical 

 mistake in the figures, or unless Dujardin had not seen the highest 

 degree of development which the syngames attain, the parasite of the 

 pheasant would constitute a distinct species, or at least a variety. 



Without wishing to decide this question, which is only possible by 

 making a direct comparison of the individuals found on different species 

 of birds, we shall give the diagnosis of Syngamus trachealis after the 

 species or variety which infests the i^heasants before offering a detailed 

 description. 



Body cylindrical, becoming with age, in the female onlj-, more or less 

 sinuous or torulose ; colored bright red by the coloring matter of the ab- 

 sorbed blood which tinges the nutritive fluid interjiosed between the 

 organs. 



Male 2""" (.079 inch) long and .2""' (.0078 inch) broad at the beginning 

 of union with the female, and reaching a length of 6'"™ (.236 inch) nnd 

 a breadth of .5™"" (.02 inch) at the end of ovulation. Body always cylin- 

 drical, surpassed in its diameter by that of the head by .2'^"' to .3'""" 

 (.0078 — .012 inch) ; posterior extremity slightly club-shaped, inclined, ob- 

 lique, terminated by a membranous bell-shaped sac or bursa, higher 

 anteriorly than posteriorly, where it is cleft and notched along its entire 

 height, supported by twelve simple rays, united to the vulva. 



Female about 5»"'> (.197 inch) long and .35""" (.0137 inch) broad at the 

 beginning of copulation, attaining a length of 20""" to 22"""^ (-787 — .866 

 inch), and a breadth at the middle of the body of 1.1"'"' (.043 inch) at 

 the end of ovulation ; body at first cylindrical with delicately striated 

 integument, becoming later more or less sinuous, torulose, and smooth, 

 the striic persisting only in the cervical region. Head 1'""' (.039 inch), 

 broad at the period of comi>lete devclo[)ment, surpassing the diameter 

 of the neck by .2""" (.0078 inch), which is itself smaller by .3""" (.0118 



