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embryos have been in water a few days they moult, losing about 

 .0005 inch in length; their tails are then more blunt. Sometimes 

 they pass through the first moult while coming out of the egg, 

 leaving the old skin within. 



THE EMBRYO IN THE EARTHWORM. 



After many careful microscopic examinations of the embryo, 

 as found in the earthworm, I have arrived at the conclusion that 

 it does not differ in its structure, so far as can be discovered, from 

 the embryo which hfis passed through one moult, after the egg 

 has hatched in water. The method of finding them in the earth- 

 worm is as follows: Select a poultry yard where chicks have had 

 the gapes for several years, so that the earthworms may have 

 plenty of the parasites. From near the surface of bare spots of 

 ground, which chicks with the gapes have frequented, take some 

 of the earthworms and examine them with the microscope. The 

 following method is recommended: Throw, the earthworm to be 

 examined into a solution of common salt (chloride of sodium), 

 having the strength of about two ounces to the pint of water. 

 When it ceases to move, rinse in pure water; then, with sharp- 

 pointed scissors, slit the worm its entire length. Spread out on 

 each side, to expose the alimentary canal. In order to intelli- 

 gently proceed, we will briefly describe the organs contained 

 therein. They consist of the mouth, pharynx, esophagus, crop, 

 gizzard and intestine. Directly connected with the esophagus, 

 about its middle and posterior part, are found six white bodies, 

 three on each side called the esophageal or calciferous glands. 

 The esophagus passes directly into the crop, which is just in front 

 of the gizzard. Following this is the intestine, which passes 

 through the remaining portion of the worm. We cut off the in- 

 testine, just back of the gizzard, and taking small pieces, about 

 one-eighth inch long, place them on a watch glass with a little 

 water, pick them well in pieces, and examine carefully with an 

 inch objective. We generally find the embryos a short distance 

 below the gizzard, not often more than half way to the tail. There 

 are numerous kinds of parasites which inhabit the earthworm, 

 some of them numbering thousands in a single worm. We have 

 also found the earthworms in different localities to harbor very 

 different kinds of parasites. The method of distinguishing the 

 embryo of Syngamus is its size, description as here given, and 



