THE MOUNT DESERT REGION 163 



Mya arenaria is one of the representative species of the 

 Myacidae, but makes up for all of the other forms by its 

 value as a food. 



The Margarites of the Trochidae are five and of very gen- 

 eral occurrence, though in small numbers. 



The Naticidae also have five forms here, with Polinices 

 her OS var. triseriata very widely distributed. 



The one species of the Skeneidae is Skenea planorhis, which 

 is found everywhere in tide pools. 



Five species of the Litorinidae occur and are our most 

 prominent Gasteropod to the eye. They are everywhere ; said 

 to be a migrant from northern Europe by way of Greenland, 

 it is now found along the entire New England coast. A quo- 

 tation from an article written in 1892 by A. E. Verrill will 

 be of interest. 



''It is well known to American conchologists that this com- 

 mon European species has become well established on the New 

 England coast within ten or twelve years, appearing first on 

 the coast of Maine about 1868; Dr. Dawson, however, states 

 that he collected it on the shores of Nova Scotia at a much 

 earlier date. I wish, at present, merely to put on record 

 some additional data as to its recent progress along the coast. 

 In 1873, it was collected in abundance at Saco, Maine, by 

 the U. S. Fish Commission, and it was found sparingly at 

 Peake's I., Casco Bay. In 1872 it was very rare at Province- 

 town, Mass., but in 1875 it was common there. In 1875 it was 

 collected by the writer at Barnstable, Mass., on the shores 

 of Cape Cod Bay, in large quantities. In 1879, it had become 

 exceedingly abundant at Provincetown. In 1875, our parties 

 found two specimens only, on the southern shores of Cape 

 Cod, at Woods Hole, but in 1876 it was found to be common 

 there, and is now very abundant. The first specimen found 

 so far westward as New Haven was obtained by Professor 

 S. L. Smith, during the past winter. Other solitary specimens 

 have since been obtained here by Mr. E. A. Andrews, and by 

 Mr. J. H. Emerton. It is, at present, exceedingly abundant 

 at Newport, R. I." 



