230 OUTLINE CLASSIFICATION OF ANIMALS 



3. Arachnoidea, including spiders, scorpions, the king- 

 crab, &c., as well as many parasites. THey have no antennae, 

 and the breathing organs are very diverse. 



The PHYLUM BCHmODERMA includes a great number 

 of marine animals, of radiate form, often with limy skeletons. 

 The living classes comprise the sea-urchins (Eohinoids), star- 

 fish (Asteroids), brittle-stars (Ophiuroids), sea-cucumbers 

 (Holothuroids), and sea-lilies (Crinoids). 



The Phylum of ANNELIDS includes all the different kinds 

 of segmented worms, ilicluding both the .sea-worms and the 

 earthworms. Among worm-like types we have also many 

 parasitic forms, of minor importance so far as distribution is 

 concerned, and such free-living ioima as Rotifers. 



The PHYLUM COELENTERA includes a great number of 

 aquatic, usually marine, organisms, often of great beauty and 

 of great diversity. Among them we have sea-firs and their 

 allies, and the fresh-water hydra (Hydromedtjsae) ; the sea- 

 anemones, corals, alcyonarians, large jellyfish and related 

 forms, all of somewhat more complicated structure (ScY- 

 phozoa) ; and finally those delicate iridescent bells which float in 

 the open waters of the ocean, and constitute the Ctenophoha, 

 because of the delicate combs by means of which they swim. 

 The sponges, all aquatic and mostly marine, constitute the 

 PHYLUM PORIPERA, and the minute PROTOZOA, of great 

 importance in that many parasitic forms are included, form 

 a large phylum of very simple animals. 



