Q20 TEST QUESTIONS FOR STUDENTS 



Arthropods and the shells of Molluscs are cuticular, and so is the 

 delicate pellicle outside the epidermis of the earthworm.] 



62. In what important respects do mites differ from lice ? 



63. In three parallel columns make a comparison between scorpion, 

 spider, and mite, as to (a) divisions of the body, (b) appendages, and (c) 

 mode of respiration. 



64. Contrast the mouth-parts in a series of Arthropods, such as cray- 

 fish, cockroach, Peripatus, centipede, millipede, scorpion, spider, tick, 

 and Limulus. 



65. Compare a crab and a beetle. In what deep ways do they 

 agree ? In what deep ways do they differ ? 



66. Classify animals according to their symmetry, [(a) Radially 

 symmetrical, e.g. jellyfish, {b) Bilaterally symmetrical, e.g. crayfish, 

 (c) Quite asymmetrical, e.g. snail. A sea-anemone is dominantly 

 radial, but the only plane that strictly halves the animal is through 

 the two siphonoglyphs. A sea-urchin is superficially radial, but the 

 only plane dividing the " test " into two similar halves must bisect the 

 madreporic plate. A heart-urchin is secondarily bilateral.] 



67. How does the shell of a typical mollusc differ essentially from 

 that of a lobster ? [Unsegmented, with conchin instead of chitin, with 

 a free edge to which additions are made as the animal grows, thus 

 not requiring to be moulted.] 



68. Discuss the zoological interest of one of the following types : — 

 Appendicularia, Apus, Archceopteryx, Balanoglossus, Neomenia, 

 Peripatus. 



69. Give an illustrated account of the life-history of one of the 

 following : — The fresh-water sponge, the hydroid Obelta, the jellyfish 

 Aurelia, Distomum, Bilharzia, Tcenia solium, Trichinella spiralis, 

 the hookworm, the common shore-crab, a barnacle, Sacculina, a moth. 

 a fresh-water mussel, an ordinary ascidian, a salmon, an eel, a frog. 



70. Arrange the characters of Amphioxus as primitive, negative, 

 and pecuUar. [It is primitive to have so many gill-slits, so many 

 gonads, so many nephridia. Negative features are illustrated by the 

 absence of limbs, skull, jaws, brain, heart, genital ducts, and so on. 

 Peculiar features may be illustrated by the cirri around the mouth, 

 the prolongation of the notochord to the very anterior end, the atrial 

 cavity, and so on.] 



• 71. Make a survey of all the difterent ways in which respiration 

 is effected in the phylum Chordata, both in young and in adults. 



72. How does a backbone differ from a notochord ? [A backbone 

 is a segmented mesodermic axis developed in the skeletogenous sheath 

 of the unsegmented endodermic axis or notochord. It is not that 

 the notochord becomes the backbone ; it is rather that the backbone 

 develops as the substitute of the notochord.] 



73. How can you tell at a glance whether you are deahng with a 

 fore-Umb or a hind-limb of a mammal, supposing them both detached ? 

 [The fore-hmb is marked by the olecranon process of the ulna ; the 

 hind-limb is marked by the round head of the femiu:, the patella at 

 the knee-joint, and the os calcis projecting backwards at the ankle- 

 joint.] 



74. What structures in an adult Vertebrate are (a) wholly ectodermic 



