342 PAKASITES OF ANIMALS 



bund condition. In the intestine there were several free 

 nematoids and also several psorosperms of the genus Monocystis, 

 so well illustrated by E. Ray Lankester. As to the nematoids, 

 which were filariform, they neither corresponded in size nor 

 structure with my strongyle embryos. 



At 1 p.m. on the 29th I renewed my examination of the 

 larva removed from the fern-pinnule. It showed a further 

 stage of growth, the male character of the reproductive organs 

 having become apparent. The now tolerably well-formed vas 

 deferens had pushed the chylous intestine on one side, whilst a 

 series of caudal rays, five on either side, supported two narrow 

 membranous wings, which represented the lateral lobes of the 

 hood of the adult strongyle. 



At 1.30 p.m. I submitted the intestinal contents of four fresh 

 earth-worms removed from my garden to microscopic examina- 

 tion, but no nematoids were found in any one of them. 



About 2 p.m. I removed another large and active strongyle 

 larva that had been reared on another fern- pinnule. It was 

 of the same size as that previously described, but was in the 

 act of changing its skin. It was then put aside along with the 

 other worm under the glass shade. 



At 3 p.m. I intended to have examined one or more of the 

 earth-worms placed in the open-mouthed phial, but all had 

 escaped and buried themselves in the fern-mould out of reach. 



At noon on the 30th I renewed my examination of the two 

 large larvae whose developmental changes I had been instru- 

 mental in producing from the time of their escape from the 

 egg-coverings. I saw no reason to doubt that the sequence of 

 changes thus far noticed referred to the species of parasite 

 under consideration. Both larvse were active, but the moult- 

 ing one had now completed its ecdysis. Its sexual distinctive- 

 ness had become yet more pronounced by the formation of 

 two rather short and stout spicules, the point of the tail dis- 

 playing a very minute awl-shaped projection. The lateral 

 membranes had not visibly increased in size. One of these 

 larvse, the first under observation, now perished from the injuries 

 sustained during inspection. 



Again, and later in the day, I sought to clear up any doubts 

 that might still suggest themselves respecting the source of 

 these larvae, by once more submitting the intestinal contents of 

 two fresh and uninfected earth-worms to careful scrutiny. In 

 the first worm no parasite could be found, and in the second 



