18 



THE POPULAR EDUCATOK. 



Creator, or both of these combined, no comparative anatomist 

 doubts that there is something absolute in nature which corre- 

 sponds more or less closely to it, as we are more or less acute 

 in our observations. 



Of course, since we can say so many things which are true of a 

 whole group of animals, but which cannot be said of any animal 

 not belonging to that group, this greatly simplifies the whole 

 study of comparative anatomy. Thus we can frame definitions 

 of groups, but there is this difficulty in this treatment of the 

 subject : we are not acquainted with all animals, and it not 

 unfrequently happens that when we have made our definitions 

 of two groups, apparently perfectly distinct, some strange 

 creature from some outlandish country is brought home which 

 has some of the characters given in one definition and some that 

 are given in the other. Then the definitions have to be re-framed 

 so as to include the new species on one side or other of the line 

 of demarcation, or a new group made for its accommodation. 

 To avoid this result, it is perhaps better to take some one 

 animal of a group which has all the essential features of its 

 group well developed, and describe it as a type, laying stress on 

 the description of those peculiarities which are the most widely 

 possessed by the members of the group. As a matter of fact, it 

 will be found that an immense number of forms cluster closely 

 around such a typical species, while those forms which lie 

 between two such types will be few and rare. This plan of 

 describing types we shall endeavour to follow ; but since the 

 human mind longs for definitions because they are definite, we 

 can hardly escape sometimes giving them. 



The animal kingdom is the realm we have to explore. How 

 is it bounded ? The question involves us in the very difficulty 

 to which we have just referred. The animal kingdom is cut off 

 from the mineral kingdom by the fact that while a mineral 

 remains unchanged unless acted on by external forces, an animal 

 is compelled to pass through a series of changes. But how shall 

 we distinguish an animal from a vegetable ? The answer which 

 would naturally suggest itself is : An animal moves and feels. 

 Yes ; but what is meant by movement and feeling ? Many 

 animals are fixed, and grow up from the rocks beneath the 

 ocean as plants do, and some plants possess not only motion 

 but locomotion. We cannot interrogate the lowest animals as 

 to whether they feel, and if we are guided by appearances, the 

 sensitive mimosa feels. The fact is, we cannot define, for what- 

 ever the definition, some troublesome species of plant or animal 

 obtrudes itself to disturb our distinction. We can, however, 

 affirm many things about plants and animals which are generally 

 true of the one kingdom and exclusive of the other. Thus, 

 animals cannot exist on mineral substances alone, but most 

 plants both can and do do so. Animals generally have an 

 internal cavity to lodge their food while it is being dissolved 

 and absorbed ; plants have no stomach. Most animals have a 

 nervous system, that is, a material by which the whole organism 

 is connected into a sentient individual, and which conveys voli- 

 tion through the frame ; no plant has a nervous system. These 

 contrasts between a typical animal and a typical plant must 

 satisfy the reader. The lower groups in both kingdoms present 

 species which it may be difficult to assign tc their respective 

 spheres ; but by keeping in mind the typical or ideal plant or 

 animal we shall usually be able to determine the position of 

 every form which presents itself. 



In the next lesson we shall give an outline of the classification 

 of the animal kingdom, only giving its main features, and not 

 descending into the minor divisions, and then take a type of 

 each class, and describe it so as to bring out its peculiar charac- 

 teristics. The student will find it a great and material help, as 

 he proceeds in his study of this subject, if he does not content 

 himself merely with committing to memory the written descrip- 

 tion of various characteristics in the construction of animals, 

 but refers to the particular animal selected as an illustration, 

 and so fixes the truth in his mind by the aid of actual ex- 

 perience. With a view to enable the reader thus to verify the 

 statements for himself, and to impress them intelligently on his 

 memory, the types chosen will, so far as it is possible, be 

 ordinary and familiar animals in each department. 



It will prevent confusion in the mind of the reader not only of 

 the following lessons, but of all books on this subject, if he 

 have a clear idea of the terms applied to the different grades of 

 the groups in classification. We give the principal names 

 employed in the order of their importance, reading from left to 



right ; and taking three familiar examples, we give the names of 

 the groups into which they fall, proceeding from the higher to 

 the lower grade. 



SUB-KING- 

 DOM OR 

 BRANCH. 



Vertebrata 

 Articulata 

 Mollusca 



GENUS. SPECIES 



Mammalia Pachydermata SolidungulaJEquus 

 Crustacea Decapoda SCaridia .Crangon 

 Gasteropoda Pulmonif era Helicida? jHelix 



COMMON 



NAME 



Caballus Horse 

 Vulgaris Shrimp 

 Aspersa Garden 

 I Snail 



A species is the lowest grade with which we shall have any- 

 thing to do, and may be defined to be that assemblage of ani- 

 mals which are alike in every essential feature of structure, and 

 any two of which (male and female) are capable of reproducing 

 their own kind in perpetuity. 



When we wish to name a species we use two names, that of 

 the genus followed by that of the species : thus science names 

 the horse Equus caballus. 



A genus is an assemblage of species ; a family a number of 

 genera, and so on. Professor Agassiz has endeavoured to define 

 all the grades, but his definitions are so vague as to be almost 

 worthless. We will not attempt to give definitions, because all 

 are open to objections, as indeed that which we have given to 

 define a species is. What is essential to the student is to 

 know that they rank one above the other, and are not used 

 indiscriminately. He will soon see how they are applied as he 

 gets to know more of the animal kingdom. 



To carry out the example given : The genus Equus includes 

 not only the horse, but the ass, zebra, etc. ; the family Soli- 

 dungula includes all animals which have a single consolidated 

 toe to each foot ; the order Pachydermata, includes not only the 

 horse family, but also the elephant family, the rhinoceros family, 

 the hog family, etc. ; the class Mammalia includes not only the 

 Pachydermata, but the Carnivora, Eodentia, etc., i.e., all brutes ; 

 and the sub-kingdom Vertebrata includes not only brutes, but 

 birds, reptiles, and fish. 



Other intermediate grades are often used, but those we have 

 given are the best established. With this explanation our way 

 is cleared for our next lesson on general classification. 



LESSONS IN LATIN. XIY. 



ADVERBS. 



IN English, adverbs are formed from adjectives by the addition 

 of ly, thus swift, swift-fa/. Similar is the manner in which the 

 Romans formed their adverbs. The ordinary terminations of 

 the Latin adverbs are c and ter ; ter sometimes stands as tier. 

 To form an adverb, find the stem and add the terminations. 

 Adverbs formed from adjectives or participles of the second de- 

 clension end in e. Adverbs formed from adjectives or participles 

 of the third declension, in ens and cms, end in ter. Adverbs 

 formed from the other adjectives of the third declension, end 

 in Her. 



You ought now to have no difficulty to know which are adjec- 

 tives of the second, and which adjectives of the third declension. 

 But for your assistance I interpose a few remarks. Adjectives 

 follow the first, the second, and the third declension of nouns. 

 Adjectives which have the nominative singular in a, and genitive 

 singular in ce, follow the first declension. Adjectives which have 

 the nominative singular in us or um, and genitive singular in i, 

 follow the second declension. Adjectives which have the nomi- 

 native singular in is, etc., and genitive singular in is, follow the 

 third declension. There are no adjectives of the fourth or fifth 

 declension. I add instances of 



ADVERBS FORMED FROM ADJECTIVES. 



Clare, clearly, brightly ; 

 LibSre, freely ; 

 Pulchre, beautifully ; 

 Prudenter, prudently ; 

 Amanfer, lovingly ; 

 Fortiter, bravely; 

 Audaciter, daringly; 



from clarus, 2, clear. 

 liber, 2, free. 



pulcher (pulchri), 2, beautiful. 

 prudens (prudent), 3, prudent. 

 amans (arnant), 3, loving. 

 fortis (fort), 3, brare. 

 audax (audac), 3, daring. 



Adverbs, like adjectives, undergo comparison. Thus,_ clare, 

 clearly, positive ; clarius, more dearly, comparative ; clarissime, 

 most clearly, superlative. Properly the comparative adverb is 

 the neuter gender singular number of the comparative adjective: 



