50 JEFFREYS. — ARCTIC MOLLUSCA. 



One difficulty will be the preservation of any soft or shell-less 

 Mollusca in high latitudes, where spirit of wine would freeze ; but 

 this may be obviated by having accurate drawings of the animals 

 made on the spot. Perhaps one of the medical staif in each 

 vessel could do this. In lower latitudes such Mollusca might 

 be kept in methylated spirit in thick glass jars, space being 

 allowed for expansion by subsequent freezing. 



The larger shell-bearing Mollusca may be wrapped up in wool 

 or paper and placed in wooden covered trays, such as were used in 

 the '' Porcupine " and " Challenger " expeditions ; and the smaller 

 shells could be kept in wooden boxes or stout pill boxes. The 

 rest of the dredged material should be carefully kept in canvass 

 bags. 



In every case, it is of the greatest consequence that the latitude 

 and longitude of the place of capture, as well as the depth, 

 should be recorded by means of linen labels, prepared so as to 

 make the print and writing ineffaceable by sea water. 



Where the ground or sea-bottom is muddy, a fine sieve may be 

 used in a large tub of water to get rid of the impalpable mud ; 

 or the " globe sieve " may be worked overboard for the same 

 purpose. A descriptive account of these contrivances will be 

 found in the preliminary report of the " Porcupine " exploration in 

 1869, in No. 121 of the proceedings of the Royal Society, p. 415. 

 I would strongly recommend also the " scoop-sieve " {loc. cit.) for 

 catching Pteropods, Cuttle-fishes, and other animals on the surface 

 of the sea. Towing-nets of muslin or fine gauze may be used 

 for the capture of small Pteropods and Oceanic Crustacea ; and 

 the stomachs of fishes and star-fishes should be examined for shells. 

 See " Hints for Collecting " in " British Conchology," vol. v. The 

 crops of sea-birds occasionally contain shells; but these shells 

 would be of littoral species and therefore not of much scientific 

 value. 



The rocks and seaweeds on the coast should be diligently 

 searched for species of Littorina, Lacuna, Purpura^ Buccinum, 

 and other littoral shells. And it should be borne in mind that 

 too many specimens of different ages cannot be collected. The 

 mischievous practice of species-making would not have been 

 carried to such an extent if naturalists had before them a suite of 

 specimens to show the range of variation, instead of being re- 

 stricted to two or three specimens, and sometimes only to what is 

 called a " unique " specimen. 



Land and fresh-water shells, when procurable, would be ex- 

 tremely interesting, and would serve to elucidate one of the diflficult 

 problems of geographical distribution. The former may be looked 

 for under loose stones and among mosses ; and the latter in pools 

 of water, dui'ing the summer and autumn. Moller described several 

 species from Greenland. 



I may add that all fossil shells should be collected, and their 

 position accurately noted, especially the height above the present 

 level of the sea. The former conditions and climate of the Polar 

 region may be thus ascertained, and a new chapter opened in the 

 history of our globe. 



