210 INVERTEBRATE ZOOLOGY 



Cocoon : a case containing one or more developing animals, 73. 



Coecum: a sac-like appendage of the digestive tract; grasshopper, 15; 

 starfish, 145. 



Ccelom : the body-cavity. 



Collar : the ventral edge of themantle in gastropods, 113 ; in cephalopods, 

 124. 



Collar cells in sponges, 183. 



Colon : a division of the intestine in insects, 15. 



Columella : the axis of a spiral snail's shell, 113. 



Compound eye : an eye made up of a number of separate elements, or 

 ommatidia, in arthropods ; wasp, 2 ; grasshopper, 9 ; crayfish or 

 lobster, 29. 



Conjugation : the fusion of two protozoans and interchange of nuclear 

 matter; Paramecium, 187; Vorticella, 190; Amoeba, 196. 



Connective tissue : a tissue whose principal function is to support and hold 

 in place other tissues and organs. 



Coxa : the proximal segment of an insect's or a spider's leg, by which it 

 articulates with the body, 4, 12, 25. 



Crop : a dilated portion of the oesophagus ; grasshopper, 15 ; earthworm, 71. 



Ctenidium : a respiratory organ in mollusks ; mussel, 93 ; clam, 107. 



Cuticula : the outer layer of the integument of most invertebrates ; wasp, 1 ; 

 beetle, 5 ; fly, 7 ; grasshopper, 10 ; spider, 24 ; crayfish or lobster, 28 ; 

 Nereis, 61 ; earthworm, 74 ; Bugula, 85 ; mussel, 89 ; clam, 103 ; snail, 

 112 ; Molgula, 136 ; tubularian, 166 ; campanularian, 170 ; Parame- 

 cium, 185; Vorticella, 189; Euglena, 192. 



Cyst : a capsule containing an animal usually in a state of suspended ani- 

 mation ; tapeworm, 83 ; Euglena, 193. 



Cysticercus : a cyst containing a tapeworm scolex, 84. 



Dentary apparatus : the five teeth and their supporting structure in the 



sea urchin, 151. 

 Development : the series of changes in the early life of an animal by which 



it passes from the condition of a fertilized egg to that of the adult. 

 Dimorphism : the condition in which a species exists in two distinct forms, 



as, for instance, male and female. 

 Distal : a position away from the point of attachment — opposed to proximal. 

 Diverticulum : a sac -like projection of a tubular organ. 

 Dorsal : on or towards the back. 

 Dorsal lamina : a ciliated ridge in the mid-dorsal line of the pharynx in 



the ascidean, 139. 



