MICHIGAN ACADEMY OF SCIENCE. 
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some of the snakes may have been carried over while hibernating in 
logs. There is little possibility that any specimens of these groups 
were ever accidentally introduced by man. The frogs, the water snakes, 
the rattlesnakes and the turtle are all more or less aquatic forms and 
probably swam across. II must be admitted however that these are 
little more than conjectures, as no data on the subject are at hand. 
Without doubt the small number of species may be accounted for by 
the distance of the islands from shore and the length of time which has 
elapsed since they became inhabitable. The number of individuals is 
also very small and this may be explained by the limited areas in the 
different habitats, which leads to a greater persecution by enemies and 
a more limited food supply. Thus the only species at all common are 
the newt, which feeds on insects in the water, and the water snake, 
which can find food in the water all about the island. The other species 
are dry land or marsh forms that on the islands are restricted to small 
areas which can only harbor a small amount of food and which are 
thoroughly worked over by the flesh -eating birds. 
LIST OF STECIES. 
1. Necturus maculosus Raf. Mud Puppy. — Altho no specimens were 
taken, Captain MacDonald reported the species as common in Saginaw 
Bay. 
2. Ambystoma jeffersonianum (Green). Blue-spotted Salamander. — 
One specimen of this salamander was taken by Mr. Wood in 1910 and six 
in 1911. They were found in the debris under decaying boards at the base 
of Snake Point. 
3. Diemictylus viridescens Raf. Green Newt. — This salamander was 
fairly common on the island. Ten in the terrestrial stage were taken in 
1910 and seventeen in 1911. In 1911, Dr. Ruthven found them common 
in a pile of decaying boards back of the light-house. On their visit to the 
island, the writers collected one which was afterwards lost, under a board 
at the base of Snake Point. 
4. Bufo americanus LeConte. American Toad. — A single specimen was 
taken on Charity Island. July 15, 1911. This toad, according to Captain 
MacDonald, had lived under the boat house for several years and was the 
only one he had ever seen on the island. 
5. Rana pipiens Schreber. Leopard Frog. — Fourteen specimens of the 
leopard frog were taken, one in 1910 and the others in 1911. The writers 
found several in August, in the high grass along the south shore of the lake. 
6. Rana clamitans Latreille. Green Frog.— Two specimens of this 
species were taken in 1910 and three in 1911. They were found under 
stones on the beach. 
7. Thamnophis sirtalis (Linn.). Garter Snake.— Three garter snakes 
were collected on the island by Mr. Wood. These were the only ones seen 
but Captain MacDonald reported it as rather common at times. 
8. Natrix sipedon (Linn.). Water Snake. — Water snakes are always 
abundant on the island. They are usually found under boards and rocks 
on the beach. Thirteen specimens were collected. 
9. Elaphe vulpinus (B. & G.). Fox Snake. — Two specimens of this 
species were killed by Captain MacDonald, about 1896. This is the only 
record for the island. 
10. Liopeltis vernalis (DeKay). Green Snake. — According to Captain 
