"Dillon--botany; Dimsdale--zoology; Douglas--chemistry," the janitor shouted once more, and the candidates moved in front of the respective tables. Tom found himself facing a great spider crab, which appeared to be regarding him with a most malignant expression upon its crustacean features. Behind the crab sat a little professor, whose projecting eyes and crooked arms gave him such a resemblance to the creature in front that the student could not help smiling. "Sir," said a tall, clean-shaven man at the other end of the table, "be serious. This is no time for levity." Tom's expression after that would have made the fortune of a mute. "What is this?" asked the little professor, handing a small round object to the candidate. "It is an echinus--a sea-urchin," Tom said triumphantly. "Have they any circulation?" asked the other examiner. "A water vascular system." "Describe it." Tom started off fluently, but it was no part of the policy of the examiners to allow him to waste the fifteen minutes allotted them in expatiating upon what he knew well. They interrupted him after a few sentences. "How does this creature walk?" asked the crab-like one. "By means of long tubes which it projects at pleasure." "How do the tubes enable the creature to walk?" "They have suckers on them." "What are the suckers like?" "They are round hollow discs." "Are you sure they are round?" asked the other sharply. "Yes," said Tom stoutly, though his ideas on the subject were rather vague." "And how does this sucker act?" asked the taller examiner. Tom began to feel that these two men were exhibiting a very unseemly curiosity. There seemed to be no satiating their desire for information. "It creates a vacuum," he cried desperately. "How does it create a vacuum?" "By the contraction of a muscular pimple in the centre," said Tom, in a moment of inspiration. "And what makes this pimple contract?" Tom lost his head, and was about to say "electricity," when he happily checked himself and substituted "muscular action." "Very good," said the examiners, and the student breathed again. The taller one returned to the charge, however, with, "And this muscle--is it composed of striped fibres or non-striped?" "Non-striped," shrieked Tom at a venture, and both examiners rubbed their hands and murmured, "Very good, indeed!" at which Tom's hair began to lie a little flatter, and he ceased to feel as if he were in a Turkish bath. "How many teeth has a rabbit?" the tall man asked suddenly. "I don't know," the student answered with candour. The two looked triumphantly at one another. "He doesn't know!" cried the goggle-eyed one decisively. "I should recommend you to count them the next time you have one for dinner," the other remarked. As this was evidently meant for a joke, Tom had the tact to laugh, and a very gruesome and awe-inspiring laugh it was too.