EXPLANATION OF THE FIGURES 



Illustrations of Animal Symmetries (Page 5) 



Fig. I. — A bilaterally symmetrical animal, with the two sides — 

 right and left — of a plane passing through the mid- 

 dle of the body alike. The European spurge hawk- 

 moth (Deile-phila eu-phorbia). 



Fig. X. — A bilaterally symmetrical animal. A curious fish (Hali- 

 eutella lappa). From Gill, after Goode and Bean. 



Fig. 3. — A radially symmetrical animal — eight similar sectors 

 surround the central axis. A jellyfish (Discofnedusa 

 philippina) from the Philippines. From Mayor. 



Fig. 4 — An animal with "biradiate" symmetry — that is, with 

 radial symmetry modified by the elongation of the 

 central mouth into a slit. A sea-anemone (Poly- 

 siphonia tuherosa) dredged from a depth of 3 ,390 feet. 

 From the Challenger reports. 



Fig. 5.' — A jointed or segmented tapeworm (Ttxnia macrocystis) 

 from a wild-cat. The head, or "scolex," is radially 

 symmetrical (four sided) but the body is bilaterally 

 symmetrical. From Hall. 



Fig. 6. — Pseudoradial symmetry. The body is divided into five 

 almost precisely similar parts, but the internal organs 

 are not all radially symmetrical, and the young are 

 bilaterally symmetrical. A sea-lily or crinoid 

 (Ftilocrinus pinnatus) from a depth of 9,52.8 feet, 

 originally described by the author. 



Different Types of Insects (Page 11) 



Figs. 7-9. — A plant-louse or aphid (Lachnus platanicola). Cour- 

 tesy of the Department of Agriculture. 



Fig. 10. — The cotton-boll weevil QAnthonomus grandis) with 

 wings extended. Courtesy of the Department of 

 Agriculture. 



Fig. II. — The grape leaf-hopper (Typhlocyba comes). Courtesy of 

 the Department of Agriculture. 



Fig. II.' — A whip-cracker butterfly QAgeronia fumosa). 



bTTJ 



