“Yes,” said Ellie.  “I know there used to be children in the water, and mermaids too, and mermen.  I saw them all in a picture at home, of a beautiful lady sailing in a car drawn by dolphins, and babies flying round her, and one sitting in her lap; and the mermaids swimming and playing, and the mermen trumpeting on conch-shells; and it is called ‘The Triumph of Galatea;’ [Footnote:  This picture which little Ellie loved so was a copy of a famous painting by the great Raphael.] and there is a burning mountain in the picture behind.  It hangs on the great staircase, and I have looked at it ever since I was a baby, and dreamt about it a hundred times; and it is so beautiful that it must be true.”

The professor, however, was not the least of little Ellie’s opinion.

“But why are there not water babies?” asked Ellie.

I trust and hope that it was because the professor trod at that moment on the edge of a very sharp mussel, and hurt one of his corns sadly, that he answered quite sharply, forgetting that he was a scientific man, “Because there ain’t.”

Which was not even good English, my dear little boy; for, as you must know, the professor ought to have said, if he was so angry as to say anything of the kind—­Because there are not:  or are none:  or are none of them.  And he groped with his net under the weeds so violently, that he caught poor little Tom.  He felt the net very heavy; lifted it out quickly, with Tom all entangled in the meshes.

“Dear me!” he cried.  “What a large pink Holothurian; [Footnote:  The Holothurians are curious creatures, such as the sea cucumbers or the sea slugs.  One genus or class of them is known as the Synapta.  These creatures are quite rudimentary, and have, as the professor’s next remark will tell you, no eyes.  A Cephalopod is higher in the scale, and has well-developed eyes.] with hands, too!  It must be connected with Synapta.”  And he took him out.

“It has actually eyes;” he cried.  “Why, it must be a Cephalopod!  This is most extraordinary!”

“No, I ain’t,” cried Tom, as loud as he could; for he did not like to be called bad names.

“It is a water baby!” cried Ellie; and of course it was.

“Water-fiddlesticks, my dear!” said the professor; and he turned away sharply.

Now, if the professor had said to Ellie, “Yes, my darling, it is a water baby, and a very wonderful thing it is; and it shows how little I know of the wonders of nature in spite of forty years of honest labour;”—­I think that, if the professor had said that, little Ellie would have believed him more firmly, and respected him more deeply, and loved him better, than ever she had done before.  But he was of a different opinion.  He hesitated a moment.  He longed to keep Tom, and yet he half wished he never had caught him; and at last he quite longed to get rid of him.  So he turned away and poked Tom with his finger, for want of anything better to do; and said carelessly, “My dear little maid, you must have dreamt of water babies last night, your head is so full of them.”