292 BIOLOGICAL SURVEY OF 



''Eeport on the Invertebrate Fauna of Vineyard Sound," 

 and subsequently (1879), listed about 140 species for the 

 whole of the New England and southern Canadian coasts. 

 Many of the species of this list, however, are of doubtful 

 validity or doubtful occurrence. Nicker son (1898) described 

 a new species of Loxosoma from southern Massachusetts. 

 Osburn (1912) listed eighty-one species and varieties in the 

 region about Woods Hole, Massachusetts, as a result of in- 

 tensive colecting for several years in a limited area. 



The present paper deals with eighty-three species and a 

 few additional varieties of Bryozoa collected in the course 

 of six summers (1926 to 1931) by the Biological Survey of 

 the Mount Desert Region, under the direction of Mr. William 

 Procter. The work of collecting and separating the species 

 was tentatively done by Dr. Henry C. Tracy, and all of the 

 material has been forwarded to the writer by Mr. Procter 

 for study. The author is further indebted to Mr. Procter 

 for the notes on the region contained in the following para- 

 graph. 



Mount Desert Island is in the extreme northeastern part 

 of the United States, Latitude 44° 20', Longitude 68° 20'. It 

 comprises about 100 square miles of exceedingly varied ter- 

 rain, with mountain peaks over 1000 feet in height, numerous 

 lakes and swamps, incised by 'creeks' and fjords, some of 

 them several miles long. The very irregular shore line is 

 bordered by mud flats, swamps, and clitfs, one of the latter 

 being the highest headland on the Atlantic coast. Outside 

 of the Island are numerous smaller islands and reefs, offer- 

 ing some protection from the open sea ; on the east is French- 

 mans Bay, with many reefs and islands, and on the west is 

 Western Bay. The Island is separated from the mainland 

 by the 'Narrows.' The climate of the Island has a July 

 average of 65°F., a January average of 24°F., and a yearly 

 average of 43°F. The water temperature average for the 

 six years, during July and August, was 58°F. at the surface 

 and 48^° F. at the bottom. The strong 10-foot tides naturally 

 tend to equalize the water temperatures to some extent. The 



