62 BULLETIN OF THE BUREAU OF FISHERIES. 



Gastropoda: 



Anachis avara (, common, living and shells). 



Astyris lunata. 



Cochlodesma leanum ( i shell). 



Crepidula convexa (i living). 



Crepidula fomicata (many shells). 



Crepidula plana (few). 



Eupleura caudata (several shells). 



Littorina litorea (i shell). 



Polynices triseriata (common, living and 



shells). 

 Tritia trivittata (many living). 

 Urosalpinx cinereus (few shells). 

 Vermicularia spirata (several shells). 



TUN1CAT.\ : 



Didcmniim lutarium (several masses). 

 Molgula manhattensis (2). 



Pisces : 



Myoxocephalus aenevis. 



Plants. 

 PhjEophyce^ : 



Desmarestia aculeata (many). 



Leathesia difformis 1 1 drift). 

 RhodophycE/E: 



Callithamnion roseum 12). 



Corallina officinalis (i drift). 



Cystoclonium purpurr.scens var. cirrhosum 

 (many). 



Phyllophora Brodiaei (many). 



Phyllophora membranifolia imany). 



Polyidesrotundus (many). 



Polysiphonia nigrcscens (many). 



Polysiphonia urceolata (i). 



Rhodomela subfusca ( i). 



2. THE DISTRIBUTION CHARTS. 



We have deemed it advisable to publish a large number of charts portraying the 

 distribution of species as revealed by the station records. It is not likely that the 

 lists of station numbers given in the text for each species will often be translated by 

 the reader into definite localities; while, on the other hand, the generalized statements 

 of the authors are necessarily incomplete and at best do not take the place of graphic 

 representations such as the charts. Some explanation is necessary for a proper under- 

 standing of these last. With a few exceptions, they are based upon the records of the 

 regular dredging stations only, i. e., those for the years 1903, 1904, and 1905.° No data 

 derived from outside information, however reliable, have been included here, nor even 

 data from our own shore collecting, or (exceptions aside) from our supplementary dredg- 

 ings and repetitions of earlier stations, though, of course, such additional data have 

 been incorporated in the text. The exceptions mentioned include the "bis" stations 

 as a whole (see p. 55), the records from which have been plotted for all species. 

 In the case of the Foraminifera, hydroids, and Bryozoa, many records derived from 

 supplementary dredgings (repeated stations) during the summers of 1 906-1 909 have 

 been plotted upon the charts. This has been considered advisable owing to the probable 

 imperfection of the original records for all of these organisms. 



Such procedure is open to two objections. In the first place, the repeated stations 

 are at best rather rough approximations to the original ones whose numbers have been 

 given them. Even with the greatest care, it is impossible to lower a dredge at precisely 

 the same point as on a previous occasion, and in the case of most of our repetitions, lack 

 of time prevented the maneuvering necessary to a very exact location of the spot origin- 

 ally charted. In the second place, the repeated stations were not distributed with any 

 regularity throughout the region dredged, and unless due caution is exercised the results 

 of these are likely to be misleading. Moreover, since the records from these have been 

 plotted only for certain groups, undue emphasis has in some cases probably been thrown 

 upon the latter. Despite these objections, however, we believe that the distributions 



n Including the completion of the ■western shore of Buzzards Bay in 1907. 



