358 DR. T. S. COBBOLD, FURTHER OBSERVATIONS ON ENTOZOA. 



EXPLANATION OP PLATE XXXIII. 



Fig. 1. Distoma conjunctum (mihi). x 25 diameters: a, oral sucker; b, ventral sucker; e, jesophageal 

 bulb; d, d, digestive caeca; e, reproductive papilla; /. uterine folds; /', egg x 220 diameters; 

 g, ovary ; h, h, excretory ducts of (i, i) the albumenogene glands ; k, k, testes ; I, contractile 

 vesicle. 



Fig. 2. A pair of the above-named Distomes, sexually connected. Slightly enlarged. 



Fig. 3. Upper fourth of Pentastoma denticulatum. x 60 diameters, with the ventral surface exposed. It 

 exhibits the mouth vrith its chitinous ring, the four cephalic claws with the hooks retracted, the 

 alternating rows of integumentary spines and stigmata, a central clear space and dark lateral 

 masses of cellular parenchyma. 



Fio-. 4. One of the cephalic claws isolated and magnified 100 diameters : a, the moveable hook ; b, tubular 

 portion of the chitinous capsule with its longitudinal groove (c) near the anterior border ; d, the 

 hood ; e, the three-cornered point-cover ; /, extensor, and g, retractor muscles of the hook. 



Fig. 5. Diagram of a portion of integument, x 250 diameters : a, spines; 6, stigmata. The spaces between 

 the rows of spines are vertically shortened one-third. 



Fig. 6. Group of parenchymatous cellules from the lateral dark masses, showing central nuclei and 

 granular contents, x 220 diameters. 



Fig. 7. Two examples of Tr'ichocephalus affinis, male and female. Slightly enlarged in breadth. 



Fig. 8. Head of one of the above, showing the small oral aperture and lateral alaform appendages. 

 X 220 diameters. 



Fig. 9. Portion of the so-called neck displaying— a, longitudinal band of epidermal cellules ; a', four of 

 the cellules under an altered focus ; b, oesophageal folds ; c, c, dermal rings ; d, d, oval cor- 

 puscles. X 230 diameters. 



Fig. 10. Spirally twisted portion of the body of a male Trichocephalus, magnified 20 diameters, showing 

 the entire extent of the penis and its sheath, without any flask- shaped expansion. 



Fig. 1 1 . Caudal extremity of the same : a, lower end of the sheath-like intromittent muscle ; b, anal open- 

 ing; c, %]\e&i\\ oi the -penis, or appendix copulatorius, with conical retroverted spines, x 110 

 diameters. 



Fig. 12. Pointed free end of the penis. x 220 diameters. 



Fig. 13. Membranous vulva of the female 7Vzc/iOce;j/<«^MS furnished with retroverted spines, and enclosing 

 the commencement of the vagina, x 140 diameters. 



Fig. 14. Four unimpregnated ova. x 220 diameters. 



Fig. 15. Fully developed egg. x ISO diameters. 



Fig. 16. Egg containing a six-hooked embryo or proscolex, removed from a free and mature proglottis, 



occupying the intestine of a common fowl. x 180 diameters. 

 Fig. 17. Egg with enclosed embryo from Tania farciminalis . x 220 diameters. 

 Fig. 18. Egg of Trichosoma mrophilum. x 230 diameters. 



