THE LOWER FORMS OF LIFE. 77 



Zoophytes is in every respect similar to the Hydra ; in fact, were 

 we to imagine the young buds sprouting and re-sprouting from each 

 other, as shown in Fig. 89 (p. 71), not to be cast off and become 

 independent individuals, but to be covered with a horny or calcareous 

 case, it would represent one of the tree-like branching Zoophytes. 



We are now prepared to see the real simplicity of the principles 

 upon which animals are classified, and I must warn those who wish 

 to gain any knowledge of zoology not to neglect this most important 

 part of the subject because it may appear dry ; on the contrary, it 

 is the very pith and marrow of the whole subject. 



The Coelenterata, as I have said, are divided into two classes 

 the Hydrozoa, which we are now considering, which have stomachs 

 hollowed out, as it were, in the substance of the animal ; and 

 Actinozoa, in which the stomach is more or less separated or free. 

 The Hydrse, which have formed the subject of this chapter, in their 

 naked form, constitute the first family, into which Hydrozoa are 

 divided, and are termed Hydridae, which is represented by a single 

 genus Hydra, and four or five species. Well, the whole family of 

 the Hydridae, being very much alike, I have not thought it necessary 

 to draw attention to its divisions. The second family, the Corynidae, 

 are those I am now treating of, and the genera differ from each 

 other in several particulars ; but all agree in the fact that the 

 polyp cannot withdraw its club-shaped body within the tube which 

 supports it. The specimen figured belongs to a genus erected by 

 Johnston, called Hermia, and the name was taken from the lines in 

 Shakespeare 



What wicked and dissembling glass of mine 

 Made me compare with Hermia's sphery eyne. 



The glandular-looking bodies at the end of the tentacles (Fig. 98, 

 p. 74) are as the guardians of the creature, the supposed " sphery 

 e'yne " which induced Johnston to characterise his new genus under 

 the name Heraiia a fanciful name enough ; but then it must be 

 remembered that all classification is more or less artificial. 



There are several genera of Corynidae. The most extensive is that 

 of Tubulari, and perhaps the best known example is that of Tubu- 

 laria indivisa, so called because each tube remains single, and does 

 not branch off like many of the others. The animal which protrudes 

 from the extremity of the tube is of a beautiful scarlet colour, and 

 the head (Fig. 100, p. 74) is crested with two rows of tentacula. 

 Several of these tubes rise from the same part of the stone, or shell, 

 upon which the root is fixed, as shown in the figure (99, c, p. 74). 

 Ellis compared the tubes to straws without joints. They are filled 

 with a reddish pink soft substance, which is connected with the head. 



