FAUNA OF PENIKESE ISLAND. 



25 



nearly dry, the absence of such forms is doubtless to be attributed 

 to the abundance of fish-eating birds on the island. It is notable 

 in this connection that the amphibia were represented by a single 

 species, the common toad, the least attractive member of the 

 class to carnivorous animals. Among reptiles, too, turtles and 

 water snakes must be extremely rare, if present at all, the only 

 reptile taken being the common garter snake, of which several 

 specimens were obtained both by the botanists on July 24, and 

 by the zoologists on August 7. Toads were also taken on both 

 days. It appears that previous collectors interested in the 

 herpetology of the island have found only the toad and the 

 garter snake. It is surprising that aquatic Crustacea were not 

 found. Not even were copepods encountered in net collections 

 from the small ponds. Perhaps in this respect, as in others, 

 the results would have been different at another season. 



Viewing the fauna of the island, as a whole, we observe that 

 it is largely arthropodan — insect, arachnid and myriapod. Ex- 

 clusive of arthropods and birds, we found but 4 species of in- 

 vertebrates (3 earthworms and i gastropod) and 3 of vertebrates 

 (an amphibian, a reptile, and a mammal). The invertebrate 

 fauna would have been greatly extended by giving consideration 

 to minute forms of animal life; but the vertebrate fauna was 

 doubtless fully covered, except as to birds, which are migratory 

 and seasonal. The apparent relative poverty of the island in 

 nearly all forms of animal life (as regards number of species) 

 may be attributed in great part to the very limited variety of 

 environments, as afforded by plants and physical conditions. 



An outstanding feature of the fauna of Penikese Island is its 

 composition (almost entirely) of forms of very general distri- 

 bution for the latitude. This, of course, is to be expected, 

 since there are no known conditions upon the island to suggest 

 the probability of the occurrence of unusual forms of life. In 

 such a place we must seek not to find a fauna of special types, 

 but rather to ascertain which of the common types of animal 

 life encounter there the conditions favorable or requisite for 

 their existence. Nevertheless, Penikese happens to be the place 

 of collection of at least one specific type. (See p. 23 above.) 



It is hoped that, quite apart from any interest which might 



