The boy jumped up as soon as he saw his friend, fairly stuttering with all the questions he wanted to ask.
"I've got to go home," the Deputy Commis
sioner said, when Colin stopped to take breath; "and you've put queries enough to keep a staff of men answering for a week! Didn't I tell you that there's a world of work to be done over the mussel? But if you like to walk along, why, I'll tell you anything I can."
"Thanks, ever so much," the boy said; "but what puzzles me in this Bulletin is the mussel's marsupium, or pouch. Has a fresh-water mussel really got a pouch like a kangaroo?"
The Deputy Commissioner pushed his hat back over his forehead.
"Colin," he said, "you have a knack of putting questions in the most awkward fashion. I suppose, in a way, the answer is 'not quite,' because in the kangaroo, the baby is almost completely formed when it is placed in the pouch, while in the mussel, only the egg goes there. The word 'marsupium' was what threw you off. What really happens is that the egg passes into this pouch or pocket in the gills, and is there fertilized as the current of water flows in and out over the gills."
"And it stays there until it has a shell of its own, doesn't it?" asked the boy.
"It does," was the reply.
"Well," said the eager questioner, "if it has
a shell and is able to look out for itself, why doesn't it? Yet the book says that it always attacks a fish and lives as a parasite for a while."