Adults and Ova 



125 



convinced by its context that Bilharz really believed that he had seen the 

 two types in the female, when he wrote the first statement, and that the 

 shape of the egg, not its colour, was what he wished to bring under notice. 

 Earlier in the same paper he describes the normal ova as terminal-spined. 

 An even more important paragraph in this paper has not been utilized 

 by Dr. Sambon. Bilharz states that this body occurred in one of the first 

 females that he examined. A drawing was made at the time, but no 

 importance was then attached to the observation. A similar condition had 

 not been met with again. Now it seems legitimate to infer that an obser- 

 vation made at the commencement of the research might not have the 

 accuracy or detail of later results when more material was available. The 



Fig. 



-A series of eggs (1 to 6) found within the uterus of the same female Bilharzia. 

 {Journal of Tropiccd Medicine and Hygiene, 1911, p. 120.) 



eggs with lateral spine are very striking objects, even when seen through 

 the body of the females, but the ordinary ova observed by Bilharz may 

 have been only apparently terminal-spined. My own suggestion is that 

 Bilharz met with one of those feu)ales seen occasionally in which egg-laying 

 has only just commenced. I have figured a series of eggs from one such 

 female in the Journal of Tropical Medicine for 1911 [271]. The outlines 

 are reproduced here. The first-formed egg (1) is lateral-spined, and lay 

 just within the vulvar opening. The others ('2 to 6) lay one behind the 

 other towards the ootype, (C) having just passed from the ootypc. All the 

 eggs were rolled to show the greatest amount of lateral displacement of the 

 spine. The later samples, it will be noticed, were incomplete and did not 

 contain an ovum. These were, in fact, casts of the ootypc in egg-shell 



