334 QUESTIONS. 



32. Of what two essential elements is a Sponge composed ? 



33. What is the nature of the " sponge-flesh ? " 



34. Describe the circulation of water in a Sponge. 



35. What are the chief variations in the skeleton of Sponges ? 



36. Whence are the Sponges of commerce obtained ? 



SI. How do the Infusorian Animalcules derive their name ? 



38. By what leading character are the Infusoria distinguished from the 

 other Protozoa ? 



39. Why were the Infusoria formerly called Polygaslrica ? 



40. Describe the Bell-animalcule. 



41. What peculiarity of the digestive system characterizes the sub-king- 

 dom Codewteraia? 



42. Of what is the body of a Coelenterate animal composed ? 



43. What is a "thread-cell?" 



44. Into what two classes are the CmUnterala divided, and what charac- 

 ters distinguish these ? Mention examples of each. 



45. What is understood by " gemmation ? " How is a compound animal 

 or colony produced ? 



46. What is meant by the term " zooid ? " 



47. What is scientifically understood by the term " individual ? " 



48. Define the terms "polypite," "ccenosarc," and "polypary." 



49. Give examples of the Hydroid Zoophytes. 

 60. Describe shortly the structure of the Hydra. 



Bl. What is the method of reproduction in the Hydra? 



62. What peculiarities distinguish the polypary of the Corynidas 



53. Give an example of the Corynida. 



54. What two sets of zooids go to form the colony of a Hydroid Zoo- 

 phyte? 



55. Define the terms " trophosome " and "gonosome." 



56. What is a " gonophore ? " 



57. What is a " medusiform gonophore ? " Why is it so called, and whai, 

 is its general structure ? 



58. Give an example of the Sertularida, and mention the difierenoes 

 which distinguish their polypary from that of the Corynida. 



■59. What is a "hydrotheca?" 



60. Describe the general structure of the reproductive bud of a Cam- 

 panularian. 



61. How do the Oceanic Hydrozoa differ from the Hydroid Zoophytes? 



62. What is a " ncctocalyx," and what is its structure ? 



63. What is a " bract ? " 



64. Mention examples of the Oceanic Hydrozoa. 



65. What is the " float " or " pneumatophore " of the Physophoridm I 



66. Of what real nature are many of the so-called Mediis<E or Jelly-fishes ? 



67. What is the general structure of a Mediisa, and with what structure 

 in the Hydroid Zoophytes does it agree ? 



68. From what circumstance is the name " naked-eyed " Mcdusce derived ? 



69. What are the "marginal bodies " of the Mcdusai? 



70. Describe Lucemaria. 



71. Of what nature are the great Sea-blubbers ? 



72. Describe " Hydra-tuba " and its development. 



73. What is the structure of a " Hidden-eyed Medusa " or Sea-blubber, 

 and from what circumstance is the former name derived ? 



74. Differences between the naked-eyed and hidden-eyed Medusffi ? 



75. Describe the generative bud of lihieostoma. 



