SYIVOAJUUS TRACHEAL.IS. 



EXPLANATION OF PLATES. 



Plate I. Fig. 1. — The trachea of an adult pheasant, whose death was caused by the 

 gapes, slit open longitudinally, and showing, in its interior and attached 

 to the mucous membrane, about thirty pairs of syngames in various stages 

 of development (natural size). 



Fig. 2. — A pair of syngames, attached with the mouth of the male and that of the 

 female (enlarged 4 diameters). 



Fig. 3. — A pair of syngames enlarged 10 diameters ; A, male ; B, female; showing the 

 intestinal canal, the oesophagus, and the buccal capsule. In the female 

 B may be seen, in addition, the uterus and its horns filled with ova and 

 the ovarian tube coiled around the uterus and the intestine. In the male 

 A the testicle is seen coiled about the digestive tube. 



Fig. 4. Mouth of a female syngame ; A, seen from its face ; B, from the side (enlarged 

 40 diameters). 



Fig. 5. — Portion of the neck of a female (enlarged 25 diameters), showing at a a the 

 cuticle finely striated ; at b the subcutaneous, fusiform, muscular fibers; 

 at c the oesophagus ; at d a salivary gland ; and at e the anterior extrem- 

 ity of the intestine into which the oesophagus opens, and which is seen 

 lined with hepatic cells. 



Plate II, Fig. 6. — Eeproductive organs of the female (enlarged 8 diameters) ; a, ute- 

 rus ; b b, uterine horns ; c c, oviducts or Fallopian tubes ; d d, ovaries. 



Fig. 7. Reproductive organs of male (enlarged 20 diameters); a, spicules; b, sper- 

 matic caual; c, vesicula seminalis ; d, testes. 



Fig. 8. — Ova in different stages of development (enlarged 260 diameters). A, vitellus, 

 segmented and muriform ; B, ovum with granular vitellus, becoming con- 

 stricted at its middle, the embryo developing laterally; C, ovum with 

 embryo fully developed, folded like the figure 8 ; D, ovum with the valves 

 . at the extremities detached, and the embryo emerging. 



Fig. 1>. — Embryo directly after leaving the egg (enlarged 260 diameters). 



Fig. 10. — Embryo somewhat older, undergoing the first molt (same enlargement). 



Fig. 11. — Nymph (enlarged 100 diameters) ; a, rudiment of the genital organ. 



5751 DA 



