INTRODUCTION. 



19 



Order 3. Turbellaria. Ex. Planarians (Planaria), Ribbon-worms 



(Nemertes). 

 Order 4. Acanthocephala (Thorn-headed worms). Ex. Echino- 



rhyncbus. 



Order 5. Gordiacea (Hair-worms). Ex. Gordius. 

 Order 6. Nematoda (Thread-worms). Ex. Round-worm (Ascaris), 



Guinea-worm (Filaria), Vinegar-eel (Anguillula). 

 Order 7. JRotifera (Wheel-animalcules). Ex. Builder-animalcule 



(Melicerta), Flexible Creeper (Notommata). 



Order 2. 



Order 3. 

 Order 4. 



SUB-KINGDOM JV.AyNULOSA. 



Animal composed of numerous definite segments or " somites, 1 ' arranged 

 longitudinally, one behind the other. Nervous system always present, con- 

 sisting of a double chain of nervous masses, or ganglia, which are placed along 

 the lower surface of the body, and form a collar around the gullet. Limbs 

 (when present) turned toward that side of the body on which the main 

 masses of the nervous system are situated. 



DIVISION A. ANARTHROPODA. Locomotive appendages, when present, 

 not distinctly jointed or articulated to the body. 



CLASS I. GEPHYREA. Ex. Spoon-worms (Sipunculus). 

 CLASS II. ANNELIDA (Ringed-worms). 



Order 1. Hlrudinea. Ex. Leeches (Sanguisuga, Hirudo). 



Oliqochceta. Ex. Earth-worms (Lumbricus), Water-worms 



(Nais). 



Tubicola. Ex. Tube-worms (Serpula). 

 Errantia. Ex. Sand-worms and Sea-centipedes (Nereis), 



Lob-worm (Arenicola), Sea-mouse (Aphrodite). 

 CLASS III. CHJBTOGNATHA (Arrow-worms). Ex. Sagitta. 

 DIVISION B. ARTHROPOUA. Locomotive appendages jointed or articu- 

 lated to the body. 



CLASS I. CRUSTACEA. Respiration aquatic, mostly by gills. Two pairs 

 of antennae. Limbs more than four pairs in number, carried upon the tho- 

 rax, and generally the abdomen also. 



"" Order 1. Rhizocephala. Ex. Peltogaster. 

 Ichthyophthira. Ex. Leruaea. 

 Cirripedia. Ex. Barnacles (Lepas), Acorn-shells (Bala- 



nus). 



Ostracoda. Ex. 

 Copepoda. Ex. 

 Cladocera.Ex. 



nia). 



Phyllopoda.Ex. 

 Trilobita (extinct). 



Merostomata. Ex. King-crabs (Limulus). 

 Lcemodipoda. Ex. Whale-louse (Cyamus). 

 Isopoda.Ex. Wood-lice (Oniscus), Slaters (Ligia). 

 Amphipoda. Ex. Sandhopper (Talitrus), Fresh -water 



Shrimp (Gammarus). 



Stomapoda. Ex. Locust-shrimp (Squilla). 

 JDecapoda. Ex. Lobster (Homarus), Cray-fish (Astacus), 

 Shrimps (Crangon) ; Hermit-crabs (Pagurus); Crabs 

 (Cancer, Careinus), Land-crabs (Gecarcinus). 

 ARACHNIDA. Respiration aerial, by pulmonary chambers or 



Order 

 Order 



Order 

 Order 

 Order 



Order 7. 

 Order 8. 

 Order 9. 



Order 10. 

 Order 11. 



..- Order 12. 



- Order 13. 

 Order 14. 



CLASS II. 



Water-fleas (Cypris). 

 Cyclops. 

 Branched-horned Water-fleas 



Brine-shrimp (Artemia). 



(Daph- 



