155 
practically nil. He therefore concludes his answer to the various 
objections made in the discussion by expressing the hope (in a form, 
by the way, which I fail to appreciate) that I would soon be able to 
provide that description of the adult forms which he himself was 
unable to produce (p. 46). I am sorry that I cannot accept the part 
thus assigned to me. If Dr. Sambon had not sufficient material to 
demonstrate beyond doubt the specific independence of Sch. vtansoni, 
he might with advantage have postponed the publication of the name 
until such necessary material was available. Since he has gone so 
far as to publish the name, and thereby implicitly claims to have 
made an important discovery, I think that it is incumbent upon him, 
and not upon me (or any other), to do the work of supplying such 
proof as the rest of the scientific world may ask. As I have already 
said, I cannot consider it as my legitimate task to prove or disprove 
the existence of a ‘ Sch. mansoni'. What I propose to do is to point 
out the inadequacies of Dr. Sambon’s theory. Doing this, i.e., 
givmg the reasons against Sambon’s theory, amounts to 
practically the same thing as giving the reasons for the views held 
by me with regard to some fundamental items in the biology of 
Sch. hmnatobium. I am not displeased to have this opportunity : for 
the rest, every reader is free to form his own judgment. 
The reasons which lead Dr. Sambon to assert the existence of a 
separate species, 'Sch. viansoni', are three: a zoological, a patho¬ 
logical, and a geographical one. The first is afforded ‘ chiefly by the 
ova. ' In Sr//. h<zmaiobiu'}n the eggs are more or less lanceolate, and 
provided with a short, straight, terminal spine ; in Sch. bovis they are 
spindle-shaped, and provided with a short, terminal, heart-shaped 
spine; in Sch. japonmim tliey are ovoid, and have no spine; and in 
Sch. mansoni they are oval and provided with a stout, lateral spine 
(1908, p. 31), The adults producing the two varieties of eggs are as 
yet indistinguishable. Dr. Sambon ‘had the opportunity of 
examining several specimens collected at post mortems in Egypt and 
Uganda.’ He ' noticed that whilst the majority of female worms 
contained within their uterine tubes the characteristic ova of 
Sch. hiematobium, with a short terminal spine at the posterior 
extremity, two presented lateral-spined ova. These had been 
removed from the gynaecophoric canal of males differing in no 
appreciable way from those clasping the more common kind. 
