874 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [2] 



laborious one. It has been endeavored to present as nearly complete a 

 set of these records as possible, but no doubt some will be found to have 

 been omitted which ought to have been included. Excepting in the 

 Arctic sea's series consisting mainly of shallow-water dredgings, such 

 as those in the Baltic, have not been included. Of other expeditions 

 which have made important dredgings no lists, so far as is known, 

 have ever been published. It will be noticed, also, that the amount of 

 detailed iofo^'mation given in these lists varies very much, some giving 

 ODly the position, depth, and kind of bottom, whilst others contain full 

 particulars of temperature of air, surface, and bottom, drift, etc. They 

 are here presented essentially as originally published, with some slight 

 changes of arrangement for the sake of uniformity, and with foreign 

 measures or temperatures accompanied with their American equiva- 

 lents. The sources from which they were derived are, as a rule, stated, 

 but with some exceptions. 



A large part of the dredging positions of the Coast Survey were 

 published by Professor Agassiz in the Bulletin of the Museum of Com- 

 parative Zoology at Cambridge, Mass. Those of 1867, 1868, and 1869 

 made by Count Pourtales have, however, been rendered definite by 

 reference to the original charts and records in the Coast Survey Office ; 

 those of 1872, made by Dr. William Stimpson, have been added from 

 the same sources, and a few other additions and corrections have been 

 made. 



The prefatory notes attached to each, both of the American and for- 

 eign lists, will render unnecessary any further explanation of their 

 sources or peculiarities here. 



The five large charts accompanying these lists require but little ex- 

 planation. They relate only to the work of the Pish Commission, Coast 

 Survey, and Challenger on and near our Atlantic coast, as it was not 

 found practicable to publish at present charts illustrating the dredgings 

 in other parts of the Atlantic and Arctic, although such have been 

 prepared. 



Every dredging made by the Fish C ommission or the Coast Survey 

 has been placed upon one or the other of these charts, except where the 

 scale compels their omission or where the position was originally so in- 

 definitely stated as to render it impossible to place it accurately. Of 

 both these classes special lists are given on the charts, pointing out the 

 nearest station which is placed on the chart. 



A few words may be added to explain the special objects of the four 

 small charts and sections placed upon the chart of the Caribbean Sea. 

 The little chart of the Gulf of Mexico and the northwestern part of the 

 Caribbean Sea serves to show parts of the Gulf not included on any of the 

 large charts, to give additional contour lines, and to direct attention to 

 the remarkable regions of deep water existing in both seas, and espe- 

 cially to that one marked as the Sigsbee Deep in the Gulf of Mexico. 

 The bottom of this is almost a perfect plain, varying in depth over a 



