EXPLANATION OF THE PLATES. 451 



Fig. 7. An isolated Trichina spiralis, after Luschka. 



a. The head. 



b. The apparently articulated tube of the intestinal canal (oesophagus) ; it attains 



its greatest size at the point b, and is filled with elementary corpuscles. 



c. Commencement of a blind tube in the posterior part of the animal, which 



encloses another tube containing dark granules (d) ; these are perhaps the 

 primordial elements of the subsequent generative organs. 

 e. The caudal extremity, with, according to Luschka, a well-marked anus with 

 three valves. 

 ., 8. Trichina spiralis, dissected, after Luschka. 



a. Expansion of the anterior part of the alimentary canal, imbedded in paren- 



chyma. 



b. The same, free. 



c. The funnel-shaped stomach, with two lateral vesicles or appendages. 



d. Continuation of the intestine below, with epithelial (flat) cells in the wall. 



e. The second tube of the lower half of the body (primordial generative 



structures). (Figures 5 — 8 after Luschka.) 



PLATE (TAB.) VIII. 



1 a. Male of Strongylus gigas, natural size, after Bremser. 

 1 b. The head, somewhat magnified, after Bremser. 



1 c. Female of the same, of the natural size, with the eggs somewhat magnified. 



a. Head and oral aperture. 



b. CEsophagus and stomach. 



c. Intestinal canal. 



d. Vagina and commencement of uterus. 



e. e. The longitudinal line along its edges. 



2 a.' Filaria hominis bronchialis, after Treutler. This is the Strongylus longevagi- 



natus of Diesing. 



2 b. A somewhat magnified view of the posterior part of the body of the male, with 



the two projecting spicules. 



3. Lower portion of the body of Filaria medinensis. The dark portion in the 



middle is the intestine terminating in the anus. 



3 a. Head of this worm with three papillae, after Birkmeyer. 



4. Male of Ascar'is lumbricoides, of the natural size. 



a. CEsophagus. 



b. Intestinal canal, 

 e. Spermatic duct. 



d. Lateral longitudinal line. The spicules are seen at the end of the tail. 



5. Female of the same worm, of natural size. 



a, b,d. As in fig. 4. 



e, e. The two uterine cords which run down to within one inch of the end of 



the tail and anus, and open externally at the vagina. 



6. The mouth, with its three hyaline flaps and comb-like muscles, with the retort- 



shaped excavated entrance to the intestinal canal. 



