carbon-dioxide to the surrounding air. Due to this system of air exchange, 
     
     this species is particularly susceptible to drying or heat. It is thought to 
     
     be restricted to woodland habitat. Cook (1984) indicates this species is 
     
     abundant in white pine, northern hemlock or deciduous woodland. It has been 
     
     noted to occur in larch stands on the Island but many more observations are 
     
     required to delineate which forest covertypes are used by this species. 
     
    
   
   
    
     TOBDS AND FROGS 
     
    
   
   
    
     The toads and frogs are collectively known as the order Anura. Five 
     
     species have been collected on Prince Edward Island and positively identified. 
     
     These are the American Toad (Bufo americanus americanus Holbrook), the Spring 
     
     Peeper (Hyla crucifer crucifer Wied); Wood Frog (Rana sylvatica Le Conte), the 
     
     Northern Leopard Frog (R. pipiens Schreber), and the Green Frog (R. clamitans 
     
     melanota Rafinesque). Four other species have been reported in adjacent 
     
     provinces but have never been positively identified on the Island. These are 
     
     the Gray Treefrog (Hyla versicolor), the Bullfrog (R. catesbeiana), the 
     
     Pickeral Frog (R. palustris Le Conte), and the Mink Frog (R. septentrionalis 
     
     Baird). The first four species can be separated with the following key. 
     
    
   
   
    
     Characteristic Species 
     
     1. Having a black eye mask Wood Frog. 
     
     1. Not having a black eye mask Go to number 2. 
     
     2. Having a diagonal cross on back Spring Peeper. 
     
     2. Not having a diagonal cross on back Go to number 3. 
     
     3. Having warts and a parotid gland* American Toad 
     
     3. Not having warts and a parotid gland Go to number 4. 
     
     4. Having a green yellowish, or black 
     
    

    
     back with indistinct, irregular spots Green Frog. 
     
     4. Having a green back with rounded or oval 
     
    

    
     spots with light edges sometimes 
     
    

    
     touching Northern Leopard Frog 
     
    
   
   
    
     * parotid glands — a pair of wartlike, external glands 
     
     located on the shoulder, neck, or behind the eye. 
     
    
   
   
    
     The Toad in Prince Edward Island is a terrestrial animal which returns 
     
     to fresh water each spring to breed. Its eggs are laid in two long strings, 
     
     one from each oviduct. The toads select temporary ponds, shallow ditches, 
     
     ponds, and slow moving water in rivers for breeding. The eggs hatch to 
     
     produce tadpoles which are black above and below, have their eyes close 
     
     together on top of the head, have horny beaks and usually have two rows of 
     
     teeth on the upper lip and three on the lower lip. The tadpoles grow quickly 
     
     and, depending on water temperature and food abundance, the tadpole transforms 
     
     into a tiny toads called toadlets in late June to August. These toadlets are 
     
     less than 2/5 inch (1 cm.) long and grow very rapidly until fall when they may 
     
     have tripled in size. They hibernate for the winter and resume growth in the 
     
     following year. After another hibernation period, the toad will return to 
     
     water to breed.