586 BIOLOGY. 



circle, namely, they repeat the Worms and Crabs, and 

 finally mount forth upon their own stage. 



The inferior or lower organized animals form conse- 

 quently two series, viz. the Smooth and Annulate, which 

 in their lower members range parallel, and that indeed 

 after the following manner : 



A. Smooth. B. Annulated or Ringed. 



I. Protozoa. I. Worms. 



a. Stomach, 1. Infusoria. 1. White -blooded Worms. 



b. Intestine, .... 2. Polypi. 2. lied-blooded Worms. 



c. Absorbents, ... 3. Acalepha). 3. Holotlmrise. 



II. Concliozoa. II. Crustacea. 



d. Veins, 4. Mussels. 4. Crabs. 



e. Arteries, 5. Snails. 5. Aselli. 



f. Hearts, 6. Kracken 6. Spiders. 



III. Ancyliozoa. III. Flies. 



g. Retia, 7. Worms. 7. Traclieoptera. 



h. Branchite, .... 8. Crabs. 8. Dictyoptera. 



i. Trachea, 9. Flies. 9. Ceratoptera. 



The Worms have simply an annulate body with re- 

 ticular or filamentary branchiae, but no feet ; the branchiae 

 are supported by the body. 



The Crabs have an annulate body with feet; the 

 branchiae are supported by limbs. 



The Insects have an annulate body with feet and 

 wings ; the body is supported by the branchiae. 



Seventh Class. 



Reticnlar, Papillose Animals Worms. 

 Protozooid Ancyliozoa. 



3503. There are Worms with a soft body and white 

 blood, without proper tentacula ; others with red blood, 

 with and without tentacula, having also bristles along the 

 sides of the body ; lastly, the rings of the body become 

 hard or muscular, and a circle or ring of osseous maxillae 

 forms around the mouth, which is usually surrounded 

 by numerous tentacula, as in the Star-fishes and Holo- 

 thuriae, in whom the blood is nevertheless colourless. 



They divide accordingly into three orders, and each of 



