HIGH SCHOOL ZOOLOGY. 



CHAPTER I. 

 The Structure of the Catfish. 



1. Botanical students will remember that plants are often 

 subdivided into phanerogamic and cryptwgamic forms ; the 

 latter lack a ■ cei-tain characteristic way of producing seeds 

 which is present in the former, but they really embrace several 

 distinct primary subdixdsions of the Vegetable Kingdom, whose 

 only common character is the negative one referred to above. 

 Similarly the Animal Kingdom is often subdivided into Ver- 

 tebrate and Invertebrate animals, but the latter really in- 

 clude several distinct sub-kingdoms sharing the negative char- 

 acter of tlie aVjsence of a backbone. Although, then, the Bo- 

 tanist and Zoologist regard the terms cryptogamic and in- 

 vertebrate as survivals from a period when less was known as 

 to the structure of the contained forms than thei-e is now, yet 

 the terms are very convenient for every-day use, becatxse they 

 separate the less important, i. e., the lower and less consincuous 

 members of the Vegetable and Animal Kingdoms f.ora those 

 which are not only higher and more familiar, but also more 

 economically important. 



2. The history of Botany and Zoology teaches us that for 

 various reasons these sciences have pi-ogressed most rapidly at 

 first with the study of the higher forms of life : similar reasons 

 will render it more convenient for us to begin our study of 

 Zoology with an examination into the structure of a Vertebrate 



