Internal Anaiomy of Uropoda Krameri. By A. D. Michael. 11 



always contain two eggs {e, e), one on each side. I have not ever seen 

 more than one egg in each oviduct at once, sometimes I have found 

 the oviduct on one side without any egg in it. These eggs are 

 extremely large in proportion to the size of the creature ; the chorion 

 is thin and almost transparent, and the embryo within may generally 

 be seen, often apparently fully-formed and ready to emerge ; but I 

 have not ever noticed any motion of the embryo as a whole, the posi- 

 tion with the legs folded closely to the body being always the same. 

 Winkler appears only to have found a single, short, unpaired oviduct 

 in Gamasus ; he does not say what there was in his species of 

 Uropoda. The two oviducts of Uropoda, Krameri terminate in the 

 median line, where they enter the short, and rather wide, azygous 

 vagina {va). This organ is also much corrugated, and is evidently 

 capable of considerable distension, it terminates in the vestibule {ves). 

 I have again used the nomenclature which I employed when I 

 described the corresponding parts in the Orihatidm. What I call the 

 " vagina " Winkler calls the " uterus." I avoided that term because 

 it conveyed to my mind the idea of an organ wherein the ovum was 

 matured or developed; now this is not the case with the part in 

 question ; the development of the egg within the body, after leaving 

 the ovary, takes place entirely in the oviduct ; the passage through 

 what I call the " vagina " must be very rapid, for I have not ever 

 found an egg in it either in Uropoda Krameri or in the Oribatidse, 

 although I have dissected very large numbers. As the oviduct of 

 Winkler's Gamasus is unpaired it is not easy to say for certain where 

 the corresponding part ends, and where the part corresponding to his 

 " uterus " begins in Uropoda Krameri; possibly his " uterus " may 

 include the homologue of a portion of the oviducts of my species, 

 particularly as he says that the egg is to some extent matured in it. 

 What Winkler calls the "vagina," apparently corresponds to what 

 I call the "vestibule," but the organ in Uropoda Krameri differs 

 greatly from anything which Winkler describes in his species ; it is 

 singular and somewhat complicated, it may, perhaps, be said to be 

 broadly lenticular in the general form of the chitinous bar which 

 surrounds its mouth, and which would be called a " ring " if it were 

 round ; but it is not truly lenticular, because, although the curved 

 sides meet sharply so as to form a point anteriorly, yet they meet 

 more vaguely so as to form a curve posteriorly. A little behind the 

 centre is a slight chitinous projection from the exterior of the bar on 

 each side, and from the inside of the bar, just opposite the projection, 

 a much slighter bar runs across the ring. The transverse bar, 

 although its direction is straight, as regards its course across the body, 

 yet curves upward a little in a direction perpendicular to the ring. 

 This transverse bar practically forms the thickened edge of the plate 

 hereafter mentioned as forming the roof of the vestibule. An exten- 

 sion or continuation of the thin membranous walls of the vagina 

 is attached round the outside of the chitinous ring, and a stouter 

 convex portion stretches across, and entirely covers the hinder half of 



