482 PARASITES OF ANIMALS 



oesophagus, Spharularia agrees neither with Gordius nor 

 Mennis, nor, indeed, with one more than the other ; since, if 

 it agrees with Mcrmis albicans in the double series of large fat 

 cells, it has no oesophagus, and in this respect more nearly 

 resembles Glordius." The reproductive organs consist of a 

 single ovary, uterus, and terminally situated vulva. These 

 organs in the full-grown females contain ova in all stages of 

 development up to the condition of advanced yolk segmenta- 

 tion; but it does not appear that embryonic formation takes 

 place whilst the eggs are still in utero. " The young animals 

 are born soon after the eggs are laid. They are about 55" in 

 length, and ^' in diameter at the broadest part. Before Sir 

 J. Lubbock conducted his inquiries the so-called male appears 

 to have been overlooked. The male, if male it be, is extremely 

 minute ; that is to say, about 28,000 times smaller than the 

 female. Notwithstanding this very circumstantial account 

 based on Lubbock's determinations, Schneider has sought to 

 show that the facts have been entirely misinterpreted. What 

 Lubbock regards as the male worm is, in Schneider's opinion, 

 a female, whilst the so-called female is nothing more than a 

 gigantic prolapsed uterus which has become many thousand 

 times larger than the body of the worm whence it proceeded. 

 It must be allowed that Schneider's description and accompany- 

 ing figures are very convincing. When revising the entozoa 

 of the Hunterian Collection in 1866 I explained the specimens 

 and dissections in accordance with Lubbock's views. In the 

 following year Prof. Huxley in his College Lectures supported 

 the view of Schneider, but in his recently published manual 

 the opinions of the Berlin helminthologist are not so much as 

 alluded to. 



Another point of special interest in connection with the 

 parasites of insects concerns the development of Mermis albionix. 

 At or near the time of the maturation of the ova, the parent worm, 

 hitherto lodged within the body of some insect, buries itself in 

 the soil. It commences its migration by boring its way out of 

 the body of the host. Some difference of opinion exists as 

 to the condition of the parent at the time of its wandering, for 

 Von Siebold asserted that it quitted its parasitical mode of life 

 " in order to become sexually mature away from the animal " 

 infested ; whereas Van Beneden states that the embryos are 

 always formed at the time of the wandering. 



From Von Siebold's experiments it would appear that in- 



