Studies in horse breeding; an illustrated treatise on the science and practice of the breeding of horses . Figure 17. Development of the foetus; ninth day:foetus; B, meeting of amnion and serosa; C, villi. A, In figure 18, can be seen a foetus of the mare at theeleventh day. At this stage of development the chor-ion (serosa) has become completely detached from theamnion. This also differs in different mammals. Itis at this stage that the serosa permanently becomesthe chorion. This has been brought about by the firstappearance of villi upon the outer surface of the se-rosa. These villi are but
Studies in horse breeding; an illustrated treatise on the science and practice of the breeding of horses . Figure 17. Development of the foetus; ninth day:foetus; B, meeting of amnion and serosa; C, villi. A, In figure 18, can be seen a foetus of the mare at theeleventh day. At this stage of development the chor-ion (serosa) has become completely detached from theamnion. This also differs in different mammals. Itis at this stage that the serosa permanently becomesthe chorion. This has been brought about by the firstappearance of villi upon the outer surface of the se-rosa. These villi are but small evaginations, or hair THE FOETUS AND FOETAL MEMBEANES OF THE HOESE 43 like growths, upon the outer surface of the ovum. Inall the figures illustrating this chapter the villi areshown at either pole of the ovum, but it is not untilthe eleventh day that they make their actual appear-ance. These villi groAV into the membrane of the uter-us, thus uniting the foetal and maternal does one ever find the branching form ofvilli in the foetal membranes of the horse, as in those. Figure 18. Development of the foetus; eleventh day: A,amniotic cavity; B, cavity of the yolk sac; C, allantois. of other mammals, and rarely does one find villi uponthe chorion in the case of the horse, except in a verysmall portion at one pole. As they are sometimesfound at both poles, the illustrations were made toshow them thus. In no mammal is there such a var-iance in respect of this as in the horse, for in some in-stances I have found no villi at the twenty-first about seventy-five per cent of cases there will beno villi except at one pole. In the attachment or con- 44 STUDIES IN HORSE BREEDING nectioii of the foetal and maternal membranes, they oc-cupy a smaller space, relatively, than of any othermammal. It is because of this, that there is neverbut a loose attachment, as compared with the mem-branes of other mammals. In figure 19, is shown a foetus at the seventeenthday. It
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecthorses, bookyear1910
