141] LIFE HISTORY OF GORDIUS AND PARAGORDIUS—MA Y 21 



ings of the two specimens are not superimposed at this time and the sperm 

 mass does not enter the body of the female but adheres to the outside. 

 The discharge usually lasts not more than thirty seconds and during this 

 time the male continues to rotate on the body of the female. The sperm 

 seems to be fluid when it leaves the body of the male but soon solidifies. 

 Some is lost in the water. 



The sperm mass (Figs. 10, 113) disappears from the female within two 

 or three days. Most of the spermatozoa pass into the seminal receptacle. 

 The mass is so tough that it is almost impossible to crush it in order 

 to make a microscopic preparation and it does not seem possible 

 that many spermatozoa are brushed off. The migration into the seminal 

 receptacle is probably passive, as the spermatozoa show no movement 

 when placed on a slide. 



The first eggs appear the latter part of April and laying continues until 

 early June. The eggs are deposited while the worms remain entangled in 

 masses among the roots of grass. They are laid in thick cords about 0.5mm. 

 in diameter and break up into short pieces from 5 to 30mm. long. When 

 fresh they are pure white, but soon become discolored by the surrounding 

 earth. They do not adhere very strongly to each other and are easily crush- 

 ed under a cover glass for microscopic examination. 



After the deposition of the eggs the adults soon become inactive and 

 begin to die and disintegrate in parts. One may actually find females 

 with the anterior end dead and disintegrated so that nothing but the cuti- 

 cula is left while the posterior end is still depositing eggs. More commonly, 

 however, disintegration does not appear until all the reproductive products 

 have been discharged and it may begin at any part of the body or the whole 

 specimen may die at once. Males usually die a week or two earlier than do 

 the females. Most of the specimens are dead by the middle of June. 



EARLY DEVELOPMENT 



Since Montgomery in 1904 gave a detailed account of the development 

 of the larva of Paragordius varius it seemed only of minor importance to 

 repeat his work on some other species and consequently little attention 

 was at first given to the embryology of this species. The observations 

 that were made, however, show that not only the larval development of 

 Gordius robustus but also that of Paragordius varius requires further inves- 

 tigation. It has not been possible to undertake that investigation for the 

 present report. 



To fill out the gap I shall give a very general account of the larval 

 development of Paragordius varius as described by Montgomery, The 

 eggs are fertilized in the cloaca and the two polar bodies are given off soon 

 afterwards. The cleavage is total and adequal and soon forms a coelo- 

 blastula which early passes over into a typical gastrula. Mesenchyme is 

 formed by the separation of cells from the invaginated entoderm. At the 



