But, before entering upon any personal explanations, it may not be out of place, in an introductory chapter such as the present, to bring under review some of the objections which have been, and still continue to be urged against this, in common with other departments of study, which are attempted to be made popular. No branch of natural history has been subjected to more disparaging opposition, partly, it must be owned, from the misplaced enthusiasm of over zealous students, than that of marine zoology. There are two classes of readers, different in almost all other respects, whose sympathies are united in dislike of such works as this. The one, represented by men distinguished for their powers of original research, are apt to undervalue the labours of such as are not, strictly speaking, scientific writers. There is another class who, from the prejudice of ignorance, look upon marine zoology as too trivial, from the homeliness and minuteness of its details. The wonders of astronomy, and the speculations suggested by geological studies, nay, the laws of organization as exhibited in the higher forms of animal life, are clear enough to this class of readers; but it is not easy to convince them that design can be extracted from a mussel, or that a jelly-fish exhibits a marvellous power of construction. Now, in my belief, the opposition of the better educated of these two classes of readers is the more dangerous, as it is unquestionably the more ungenerous. If Professor Ansted, when treating of the surprising neglect of geology, could thus express himself--'How many people do we meet, otherwise well educated, who look with indifference, or even contempt on this branch of knowledge,'--how much oftener may the student of the humble theme of marine zoology bewail the systematic depreciation of persons even laying claim to general scientific acquirements. This may be illustrated by an observation, made in a northern university, by a celebrated professor of Greek to a no less celebrated professor of natural history. The latter, intently pursuing his researches into the anatomy of a Nudibranche lying before him, was startled by the sudden entrance of his brother professor, who contemptuously advised him to give up skinning slugs, and take to more manly pursuits. There is one light in which the study of marine zoology may be regarded, without necessarily offending the susceptibilities of the learned, or exciting the sneers of the ignorant. The subject may be pursued as an amusement--a pastime, if you will; and it is in no higher character than that of a holiday caterer, that the author asks the reader's company to the sea-side. No lessons but the simplest are attempted to be conveyed in this little volume, and these in as quiet and homely a style as possible.