CONCLUDING EEMAEKS. 295 



remains unappreciated by the mass of even so-called enlightened humanity. 

 In common with all other animals, the engrossing care of man is food for 

 the stomach, while intellectual food too often remains unknown, is disre- 

 garded or rejected. 



"Going fishing ?" How often the question has been asked by acquaint- 

 ances as they have met me, with rod and basket, on an excursion after 

 materials for microscopic study. Yes ! has been the invariable answer, for 

 it saved much detention and explanation, and now, behold, I offer them 

 the results of that fishing. No fish for the stomach, but, as the old French 

 microscopist Joblet observed, "some of the most remarkable fishes that 

 have ever been seen " ; and food fishes for the intellect. 



To my pupils, both of the University of Pennsylvania and Swarth- 

 more College, but especially the boys and girls of the latter, who have 

 attended my lectures on natural history, the work will be of interest, as 

 they will recognize in its illustrations many of the simplest forms of animal 

 life with which they have been made familiar through my instruction. 

 Indeed, in the course of preparation of the book I have always had my 

 pupils in mind, and I shall be glad if it serve as an additional aid to their 

 studies. 



In conclusion, I embrace the opportunity of thanking those of my 

 friends who have not only expressed a warm interest in my investigations, 

 but who have aided me in my excursions, or who have collected materials 

 in distant localities and sent them to me. Among them, especially, I take 

 the liberty of mentioning Dr. Robert S. Kenderdine, Rev. Thomas C. 

 Porter of Easton, Dr. Joseph K. Corson, U. S. A., Joseph Willcox, Dr. 

 Isaac Lea, Clarence S. Bement, and Chai'les E. Smith. 



