XXVI DESCRIPTION OP PLATES. 



PLATE XX. 



1. A female example of Dractmeulus medinensis of tlie natural size. 



2. Caudal extremity of the same ; considerably magnified. 



3. Enlarged view of the head, showing its truncate form and the position of the 



equidistantly situated cephalic papillEe ; magnified. 



4. View representing the field of the microscope with numerous embryos in focus. 



Drawn with the aid of a camera (x 60 diam.). 



5. One of the embryos naturally coiled upon itself (x 500 diam.). 



The above figures are original. — T. S. C. 



PLATE XXI. 



1. A male example of Pentastoma tcenioides. Natural size. 



2. A female specimen of the same worm. Natural size. 



3. Upper fourth of the body of the so-called Pentastoma dentioulatum, showing 



the mouth, cephalic claws, integumentary spines, stigmata, and internal 

 glandular parenchyma (x 60 diam.). 



4. One of the claws isolated ; a, moveable hook ; b, tubular portion of the 



capsule ; c, longitudinal groove ; d, hood ; e, the three-cornered point-cover ; 

 /, extensor, andy, retractor muscles of the hook (x 100 diam.). 



5. Diagram of a portion of integument (with the spaces between the rows of 



hooks shortened) ; a, spines ; 6, stigmata (x 250 diam.). 



6. Parenchymatous glandular cellules (x 220 diam.). 



7. Egg of Pentastoma tcenioides, with its contained embryo. — Leuckart. 



8. Embryo of the same after its escape from the egg. — Leuckart. 



Figs. 1 to 6, inclusive, are original. — T. S. 0. 



