Perkins.] 110 (October 6, 



called Savin Kock, though the name belongs properly to the largest 

 only. Everywhere else the shores are low, sandy and faced by 

 broad mud flats. A few of the species were collected in the some- 

 what clearer and deeper water of the Sound, outside the bay. On 

 account of the freshness and impurity of the water, many species are 

 less brightly and beautifully colored, and smaller than in more favor- 

 able localities. Some genera, as Pecten, Ensatella and Hemimactra, 

 which are very abundant north or south, are relatively uncommon 

 and small, while others, as Macoma, grow very large. Deep water 

 species are necessarily either wholly wanting, or occur only as dead 

 shells thrown upon the beach by storms. The fauna of the region 

 belongs about equally to the Acadian and Virginian faunae. 



Of the marine species enumerated, fifty occur north of Cape Cod, 

 thirteen Dr. Packard reports from Labrador, eight are found in 

 Greenland, according to Dr. Morch, and eight are European. Fifty- 

 one extend as far south as South Carolina, and some still farther. 

 Thirty-seven are found in the Post Pliocene, twenty-six in the Plio- 

 cene, and nineteen in the Miocene. Of the sixty-five species found 

 in the Sound, but not, as yet, in New Haven Bay, forty-nine are 

 found north of Cape Cod, and nine on the Carolina shores, while 

 others range both north and south. 



The descriptions of the animals, and all measurements, are from 

 living specimens, and the various parts are taken in their natural 

 position. In bivalves the length is regarded as the distance from the 

 siphonal end to the opposite. 



In nomenclature the rules of the British Association are followed. 

 The list of marine species embraces all that have hitherto been found 

 in this place, and is the result of a careful examination of the whole 

 region. It has been impracticable at this time to give as thorough • 

 study to the land and fresh water shells, though the list is believed to 

 be tolerably complete. The sandy soil, trap and sandstone rocks of 

 the region are not favorable to the growth of land shells. I am happy 

 to express my sincere thanks to Professor A. E. Yerrill for granting 

 free use of the Yale College collection, for freely giving his personal 

 assistance at all times, and for identifying the Polyzoa. I am also 

 indebted to Dr. E. T. Nelson and Mr. H. S. Williams for the use of 

 their collections. 



The following works are referred to in the Synonymy : — 



Sy sterna Naturae. Linne. 12th ed. 176 7. 



Animaux sans Vertebres. Lamarck. 12th ed. Paris, 1843. 



