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.