ZooL.— Vol. II.] EISEN—OLIGOCHMTA. 249 



The after treatment offers no peculiarities and is understood by every biolo- 

 gist accustomed to laboratory work. The worms are preserved in alcohol 

 which should be changed as soon as it becomes yellow, or in a solution of 

 formaldehyde in water, or in a one per cent, solution of formaldehyde in 

 thirty per cent, of alcohol. Specimens should on no account be kept any 

 length of time in strong formaldehyde, as it greatly injures them. 



Some worms contain sand or other hard substances, which must be gotten 

 rid of before sectioning. An easy method is to cut the specimen lengthwise 

 with a pair of fine scissors, and then to wash the sand from the intestine. In 

 this way one-half of the body may be sectioned lengthwise and the other half 

 transversely. 



The sections are best mounted on slides by the alcoholic method (Eisen 23). 



When the worms are removed to vials, they should be placed head down- 

 wards, in order to prevent this part from becoming accidentally dried. Do 

 not place too many specimens in one vial, as they will macerate and 

 become useless. If, however, space is limited and it is desirable to crowd 

 the specimens, the formalin solution may be changed several times until it 

 remains perfectly clear after standing for several days. The worms must be 

 hard and solid when stored away. It is very important that the vials should 

 be full of the solution, so that when turned about the worms will not move. 

 A piece of paper placed in the top of the vial will also prevent any shaking 

 up. Fill the vial full of liquid, drop a string down into the neck of the vial and 

 then insert a cork. Press down the cork and at the same time pull out the 

 string. The air in the bottle will escape and the cork can be pushed down 

 to the very liquid, thus leaving no room for air. Even comparatively small 

 air bubbles will allow the contents of the bottle to shake about, causing the 

 ruin of the specimens. The best paper to place in the bottles is soft white 

 tissue paper. Toilet paper will not do as it dissolves. 



When glass vials are to be sent away they should always be packed in a 

 box which is enclosed in another box, with soft packing between the two. 

 A label of stiff paper on which is written in lead pencil the date and locality, 

 and whether collected in soil, in the mud of rivers, in moss, etc., should 

 always be placed inside the vial. 



Disappearance of Native Species. 



It is not my intention to enumerate here all the localities in which native 

 worms abide; indeed, they are to be found almost everywhere in the soil, and 

 in the banks and bottoms of rivers and streams. In collections received from 

 generous friends and donors it has often been a great disappointment to find 

 the large majority of the specimens to be worms imported from Europe, 

 instead of native species, which are the only ones of real interest to us. 



Collectors generally hunt for earthworms in manure piles or in gardens, and 

 it is in just such places that the accidentally imported European worms flourish 

 to the exclusion of the native species. In California and in the southern 

 States generally, it is now almost impossible to find in rich garden soil and in 

 manure piles any other than common, European varieties. 



Native Oligochaeta are to be found in the virgin soil of the country, far from 

 gardens and manure heaps; in the moist soil of gulches and mountain meadows; 



