42 ZOOLOGY SECT, i 



need not be described here, are referable to the phylum Mollusca. 

 Other familiar animals are readily to be recognised as belonging to 

 one or other of these great phyla. A Prawn, a Crab, a Blue-bottle 

 Fly, a Spider, are all on the same general plan as the Lobster : they 

 are jointed animals with jointed limbs, and they have the internal 

 organs occupying similar positions with relation to one another. 

 They are all members of the phylum Arthropoda. Again, a Mussel, 

 a Snail, a Squid are all to be set side by side with the Oyster as 

 conforming to the same general type of structure ; they are all 

 members of the phylum Mollusca. While a Dog, a Lizard, a Fowl 

 are obviously nearer the Fish : they all have skull and back- 

 bone, brain and spinal cord, and two pairs of limbs ; they arQ all 

 members -of the great group Chordata. 



Altogether twelve phyla are to be recognised, viz. : 



I. Protozoa VII. Molluscoida 



II. Porifera VIII. EcTiwwdermata* 



III. Ccelenterata IX. Annulata 



IV. Platyhelminthes X. Arthropoda 

 V. Ncmathdminthes XI. Molhisca. 



VI. TrocJielruintlus XII. Cliordata 



