THE NAUTILUS. 129 



OxYCHONA MiMARUM Ancey. 



Oxychona bifasciata var. mimanim Anc, Le Nat., 1901, p. 93. 

 Pilsbry, Man. Conch. XIV, p. 154. This unfigured form from 

 Minas Geraes is probably specifically distinct. Not seen by the 

 writer. 



A LIST OF MOLLUSKS COLLECTED AT CASTLE ISLAND, BOSTON. 



BY SHIELDS WARREN. 



Castle Island, Boston Harbor, is an interesting collecting 

 ground owing to the number of mollusks that flourish there 

 under the adverse conditions necessarily present in a great sea- 

 port. The main channel to the inner harbor passes the island, 

 and every ebb-tide strands much of the water-front debris on its 

 shores. Although the island would seem an unfavorable habitat 

 for even hardy mollusks, it is one of the best collecting places 

 for nudibranchs in the vicinity of Boston. In the early spring 

 considerable numbers come there to breed, particularly Acanlho- 

 doris pilosa and Lamdlidoris bilamellata, and I have found scat- 

 tered specimens of these and other species from October to June. 



The shore of the island on the east and south is sand and 

 gravel with scattered boulders, and is sand and mud, with 

 patches of eel-grass, elsewhere. Between Castle Island and City 

 Point are extensive mussel flats ; and clay, dredged from the 

 neighboring channel and dumped beside the bridge, contains 

 numerous valves of oysters and quahaugs similar to those found 

 in the excavations for the Boylston Street Subway. Litorina 

 littorea is very plentiful on the rocks and is gathered by the 

 Italians for food. The imbricated form of Thais lopillus is fairly 

 abundant. 



Below is a list of the mollusks I have collected on the island, 

 and which seems to be fairly representative of the whole of 

 Boston harbor. Species marked with an asterisk have not been 

 obtained living. 



