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Updated: June 1, 2025
In proof of the fact that the special features of the mammals have been inherited by man, I will, in conclusion, point out the identical way in which the ova are formed in the ovary. There again, as in the whole of his morphology, man proves indubitably his descent from the mammals.
The method of obtaining the young lobsters is different from that employed to rear trout from ova. The female lobsters carry all their eggs fastened to hair-fringed fans or "swimmerets" under their tails, the eggs being glued to these hairs by a kind of gum which instantly hardens when it touches the water.
With lowly-organised aquatic animals, permanently affixed to the same spot and having their sexes separate, the male element is invariably brought to the female; and of this we can see the reason, for even if the ova were detached before fertilisation, and did not require subsequent nourishment or protection, there would yet be greater difficulty in transporting them than the male element, because, being larger than the latter, they are produced in far smaller numbers.
If, then, the fully developed and mature can resist such powerful extraneous causes of destruction, how much more must the ova possess the power of enduring them without losing their latent life! The following extract from Professor Owen's Lectures shows the bearing of these facts upon the question of equivocal generation.
The males give out masses of sperm, and the females discharge ova in such quantity that many of them stick to the fibrils about their mouths. Both kinds of cells pass first into the mantle-cavity after the opening of the gonads, proceed through the gill-clefts into the branchial gut, and are discharged from this through the mouth. The ova are simply round cells.
Nor, if we admit personal identity between the ovum and the octogenarian, is there any sufficient reason why we should not admit it between the impregnate ovum and the two factors of which it is composed, which two factors are but offshoots from two distinct personalities, of which they are as much part as the apple is of the apple-tree; so that an impregnate ovum cannot without a violation of first principles be debarred from claiming personal identity with both its parents, and hence, by an easy chain of reasoning, with each of the impregnate ova from which its parents were developed.
Before puberty, the ova have lain asleep, as it were, in a cocoon state. Now with puberty they awaken. And with them all those profound mechanisms and inventions that have to do with their nutrition up to ripening.
In volvox they are entirely subservient to, and exist for, the reproductive cells, and die when they have completed their service of these. The body is here only a vehicle for ova. Furthermore, in volvox there has arisen such an interdependence of cells that we can no longer speak of it as a colony.
If he adheres to his own version, I would merely observe that there is no analogy in the two cases. But the inference does not rest upon mere supposition; the freshwater shrimps at Knowlmere were seen devouring the ova in the spawning-boxes. We have seen above that Par eat ova as well as Trout.
R. Buist, the superintendent of the Stormontfield experiments, says that in 1865, out of 70 salmon first landed for the purpose of obtaining the ova, upwards of 60 were males. In 1867 he again "calls attention to the vast disproportion of the males to the females. We had at the outset at least ten males to one female." Afterwards females sufficient for obtaining ova were procured.
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