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and Astacus pass through the Nauplius stage before they 

 are hatched out. The " winter eggs " of Daphnia (water- 

 flea) develop into parthenogenetic females which produce 

 the " summer eggs " that are never fertilised. See Parthe- 

 nogenesis, page 13, Part I., " Catechism," Zoology. 



CLASS PROTOTRACHEATA. 



Describe the External Appearance of Peripatus. What is 

 its Zoological Interest, and where is it found ? 



Small and caterpillar-like, the body soft and rounded 

 and bearing numerous pairs of soft and cylindrical limbs 

 with claws. One pair of antennae, at the bases of which are 

 the eyes ; a pair of jaws and a pair of oral papillae, which 

 secrete slime for securing prey. 



Peripatus is a connecting-link between Annelid worms 

 and tracheate Arthropods. Its Annelid features are : 

 Thin cuticle, hollow appendages, simple eyes, a muscular 

 pharynx, stomodaeuir and proctodaeum short, a series of 

 paired nephridia, and cilia (in the genital ducts). Its 

 Arthropod features are : Antennae, appendages modified 

 as jaws (gnathites), heart with ostia communicating with 

 pericardium, reduced coelome and extensive haemocoele, 

 and respiration by tracheae or air-tubes. 



It is terrestrial, and like certain other primitive creatures, 

 it has a discontinuous distribution, i.e., it is found in regions 

 of the world far apart (e.g., one type of Peripatus occurs 

 only in Chili and in South Africa). 



CLASS INSECTA. 



State the General Features of Insects. 



The cuticle is chitinous, parts of it are thickened (scler- 

 ites), and it forms the exoskeleton. The body of the adult 

 shows three distinct regions : head, thorax, and abdomen. 

 The head (with or without a neck) has simple or compound 

 eyes (or both) and bears one pair of antennae and three 



K 



