The Argonaut. Paper Nautilus 



shelly substance are constantly added. Serious breaks in the 

 delicate porcelain shell are repaired by this web; the strangest 

 recorded incident is of the cementing in of a broken piece, but 

 wrong side out. 



There is no union by muscle bands between shell and body. 

 The arms simply hold it fast, and in such position that the eggs 

 from the beginning are protected by being lodged in the coil of the 

 shell, with the body between them and any harm. 



The report of Madame Power's investigations was made by 

 Professor Richard Owen before the Biological Society of Lon- 

 don in 1839, and the question of whose shell the Argonauta lived 

 in was settled once for all. The cause of science took a mighty 

 step forward. For this quiet student proved that observation, 

 not argument, is the straightest road to truth. 



Fourteen years later, in 1853, Miiller identified and pub- 

 lished a full description of a tiny octopus, the male of Argonauta. 

 Investigations of an earlier date had just demonstrated that the 

 supposed parasite in the mantle cavity of the female is one of the 

 eight arms of the male, modified as a bearer of the spermatophores. 

 The arm ends in a whip-lash. In this is a passage through which 

 the spermatophores pass out into the mantle cavity. A kind of 

 spring in each spermatophore is released, scattering the dart- 

 like spermatozoa over the exposed ova. Union of sperm cell 

 yith ovum cell is called "fertilisation." Now the nidamental 

 glands pour a viscid substance over the eggs, which hardens, 

 forming a series of globular capsules, all joined together into a 

 compound cluster, like a bunch of grapes. The useless hectoco- 

 tylised arm is now discarded. The egg cluster is crowded back 

 into the spiral. Gradually its increasing size crowds the moUusk 

 out of her seat. Then the egg mass, still firmly attached to the 

 body of the female, floats upward in the water, until the young 

 hatch and swim off as free individuals. 



When the fragments of evidence were brought together they 

 fitted so well that scientists wondered greatly at their own 

 stupidity. For had not Aristotle told them that the polypi of 

 the Mediterranean had one arm swollen and distorted at the 

 breeding season ? Even the fishermen knew this. We now know 

 the hectocotylised arm to be a constant character among all 

 cephalopods except the pearly nautilus. In only three genera, 

 however, is it detached. 



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