HELMINTHOLOGY HELMINTHES NEMATODES. 459 



assumes the capillary figure of the Sperinatozoida in the 

 Neinatoda with too great certainty. The Reporter has 

 never seen spermatic filaments in round worms, nor also 

 has Kolliker ; but he appeals to Mayer's researches without 

 actually confirming them. 



When the development of the embryo of Ascaris dentata 

 commences, the germinal vesicle with its germinal spot 

 immediately disappears ; whereupon the primitive nucleated 

 embryo-cell is formed, which is rather larger than the ger- 

 minal vesicle. In this primitive embryo-cell two new 

 nucleated cells are produced, which are liberated on the dis- 

 appearance of the primitive embryo-cell. These two cells 

 become again mother-cells, and are subdivided into two cells, 

 by which means four embryo-cells are produced. Each of 

 these four cells, as also the succeeding ones, are broken up 

 into two cells, by which means the vitelline cell, the granules 

 in which during this process gradually disappear, is finally 

 completely filled with embryo-cells. This mass of cells 

 becomes the body of the young worm. At first the nuclei 

 are still apparent in the embryo-cells, but in proportion as 

 they become less their nuclei are less perceptible. Kolliker 

 observed a precisely similar course of development of the 

 embryo in the ova of Oxyuris ambiyua. During this pro- 

 duction of embryo-cells a very remarkable change goes on, 

 the chorion of the OATiin in Ascaris dentata, consisting 

 in the formation at each extremity of a process, which, con- 

 tinuing to shoot out longer and longer, becomes spirally 

 twisted, and breaks up into very delicate, equal-sized, also 

 spiral filaments, or fibres. For those who may be desirous of 

 repeating some of Kolliker's researches on his Asc. dentata, 

 the Reporter remarks that this worm, according to Kolliker's 

 statement, was procured from the intestine of Salmo thy- 

 mallus, whilst Ascaris dentata has hitherto been met with 

 only in the Cyprinaceae, and, according to Rudolphi, possesses 

 simple " ova globosa." Is it not probable that Kolliker had to 

 do with Asc. obtuso-caudata, which occurs extensively in the 

 Salmonidse? In Ascaris nigrovenosa, acuminata, and succisa, 



