INVERTEBRATA. 457 



18. Describe in detail the gill of a mussel. What are the 

 functions of the gills ? 



19. Give an account of the body cavity of the mussel, and 

 compare it with that of any vertebrated type (say which 

 you take). 



20. Describe fully the circulatory and respiratory organs 

 of a crayfish, and compare them with those of a mussel. 



21. Describe the urinary and generative organs in (a) 

 Astacus, (b) Lumbricus, (c) Anodon. (d) In what respect do 

 the urinary organs of Lumbricus and Anodon resemble one 

 another and differ from those of Astacus ? (e) What is the 

 function of urinary organs ? 



22. Draw diagrams of the blood vascular system of (a) 

 Lumbricus, (b) Astacus, (c) Scyllium. Describe the course of 

 the circulation of the blood in each of these animals. 



23. Describe the digestive organs of Astacus, including the 

 mouth appendages. 



24. Describe the heart of the frog and compare it with 

 that of the crayfish. 



25. What is meant by the term ccelom ? G-ive a short 

 account of the coelom in Lumbricus, Eana, and Lepus, 

 including (1) development, (2) relation to the gonads and 

 gonaducts. 



26. What is the nature of the renal excretion ? Describe 

 the structure and exact position of the excretory organs in 

 the earthworm, mussel, crayfish, and frog. 



27. Describe the microscopical characters of the cir- 

 culatory fluids met with in the rabbit, frog, Astacus, and 

 earthworm. 



28. Describe and compare with one another by means of 

 diagrammatic figures the structure of the eye in (1) Astacus, 

 (2) Eana or Lepus. Explain briefly the mode of action of the 

 compound eye. 



29. In the series of organisms (1) Amceba, Paramecium, 

 Hydra, Earthworm, Frog ; (2) Spirogyra, Fucus, Pteris, 

 Vicia (Bean Plant) ; show that the structures characteristic 

 of the animals as such, whether high or low on the one 

 hand, and of the plants as such on the other, are the 

 expression of a fundamental difference in the mode of 

 nutrition of the members of the two series. 



