None of the transparent involucra were visible in this Ovum, when, after excruciating and prolonged sufferings, it was expelled in the intact state here represented. The external or placental envelope invests the entire Ovum, and explains the cause of the abortion. The artist has seized with much felicity the uneven and almost cribriform surface of the fleshy envelope, exhibiting numerous orifices, through which its adherence to the uterine vascular lining, resulting from the act of fecondation, was effected. Fig. 11. We here see the immediate and direct effects of the peculiarity of an _entire placental covering_, as represented in the preceding Ovum (10.). The secreting or inner involucrum (amnion) of that Ovum, when laid open, was found tinged with blood and the cord distended by the same fluid which pervaded also the _liquor amnii_, as well as the fœtus itself. The morbid adhesions, contracted by the middle membrane with the chorion in consequence of plethora, are well marked in one part of the drawing by the artist to whom I carefully dissected the preparation. The chorion itself is in a morbid state. Fig. 12. Ovum opacum plethoricum. (Eleven weeks after menstruation.) Placental or cortical covering, lying over three-fourths of the Ovum. A pellucid membrane entirely surrounds the placental covering to which it adheres. The chorion is thickened, and has contracted morbid adhesions with the middle membrane. The transparent or inner involucra are easily separated into four laminæ, three of which belong to the middle membrane.—(Dutrochet.) The liquor amnii was of a brilliant red colour—the cord large, flattened, and the vein ruptured. Here we see the same direct consequences from the same defects in the structure of the Ovum which we noticed in Fig. 11. This abortion was brought to me by a midwife immediately after its expulsion. I carefully examined and dissected it, and before the least change could take place in its parts or colour, it was drawn by Mr. Perry (1827). No hemorrhage followed the expulsion of this Ovum. The woman had had several children, and miscarried three times between every two successful pregnancies; whereupon her general health was greatly impaired. REMARKS. These two morbid Ova are represented of their natural size, and were carefully drawn and coloured as soon after their expulsion as could be accomplished. I believe they are unique of their kind. At least I have not seen any such in the various collections I have visited: neither do I think that they have been mentioned, still less delineated, by any writer.