390 



Marvels of the Universe 



f.Z/^M' 





A MICROSCOPE 

 SLIDE. 



In the blacU ring are 

 some Diatoms of the 

 natural size, like specUs 

 of fine dust. 



and the race of which they are 

 members is that of the cuttle-fishes. 

 Imagine a cuttle-fish clasping with 

 two long arms a large oval and not 

 vevy wide snail-shell which looks as 

 though it were made of crinkled 

 tissue-paper, with the greater part 

 of its body and the remaining arms 

 hanging outside the shell, and you 

 will have a very fair idea of the 

 appearance of the Paper Nautilus. 

 The first actual observations 

 recorded of their habits are those 

 of Mme. Jeannette Power, who 

 studied these creatures in her viva- 

 rium at Messina. She states that 

 the young Nautili are naked when 

 they issue from the parent shell, 

 but that in the females the shell 

 begins to form within ten or twelve 

 days. Its formation is due to a 

 secretion exuded from the two 

 large tentacles which sweep back- 



Pholo bii] 



A DIATOM AND A 



The centre of the slide 



eighty times, with a human 



[i'. J. Spitla. 



HUMAN HAIR. 



here sho^vn enlarged 



hair stretched across. 



The black hand is the hair, and beside it is a Diatom, 



to which an arrow points. The same Diatom is 



shown at the foot of the page on a larger scale. 



wards from the creature's beak over the bag-shaped body. Should anything happen to this 

 delicate construction the owner is able to repair it in the same way that any other mollusc can repair 

 his home, except that the tools here used are different ; for most molluscs obtain their secretion 

 from the mantle which lines the interior of the shell, while the supply of the Nautilus is derived 

 entirely from her two tentacles. These tentacles fulfil another important purpose, for they act 

 as spiTng clasps to this frail cradle (now become the treasure-house of the eggs of the Nautilus), 

 and press it against the bag-shaped body, which entirely fills up the opening of the shell, so that 

 the eggs may be securely packed in their appointed vessel. To better serve the purpose of security, 

 each tentacle is supplied with a fine membrane, which spreads out like a web from the central ridge 

 and can be made to fold over the greater part of the cradle, adhering closely on account of its 

 elasticity' to the ridges and depressions in its surface. 



There are several species of the Paper Nautilus, all of which are found in the warm seas. The 

 most common is that found in the Mediterranean, such as is depicted on page 389, while the first 

 illustration shows a very beautiful variety, noticeable for its network ridges and the bolder toothing 

 along the crest of the shell. 



Photo b«] [Max Poser, F.R.M.^. 



A BEAUTIFUL DIATOM. 



The central area of this graceful form is marked with fine cross-lines. Only line lenses of high power can separate these 

 lines. The original photograph from which this block was made was on a scale of 3.600 times the natural size : here it i& 

 reduced to half that scale, or 1.800 times. 



