APPENDIX 229 



PHYLUM VIII. ECHINODERMATA 



Radially symmetrical animals with calcareous plates or spicules in the 

 body wall. 



Class I. Crinoidea, Sea lilies. Echinoderms which are sessile through- 

 out Hfe or only as larvae. Ex. Comatula. 



Class 2. Asteroid ea. Starfish. Flattened, star-shaped echinoderms with 

 an ambulacral furrow on the under side of each ray. Ex. Asterias. 



Class 3. Ophiuroidea, Brittle stars. Flattened echinoderms with long, 

 vibratile arms and without ambulacral furrows. Ex. Amphiura. 



Class 4. Echinoidea. Sea urchins. Spheroidal or flattened echinoderms 

 without arms. Ex. Arbacia. 



Class 5. Holothurioidea. Sea cucumbers. More or less wormlike echi- 

 noderms with oral tentacles. Ex. Synapta. 



PHYLUM IX. CHORDATA 



Animals with a dorsal central nervous system, an internal skeletal system, 

 consisting in the simplest cases of the notochord, and paired pharyngeal 

 slits and arches. 



SuBPHYLUM I. Enteropneusta. Wormlike chordates with a large pro- 

 boscis in front of the mouth. Ex. Balanoglossus. 



SuBPHYLUM II. Tunicata. Chordates in which the body is inclosed in a 

 tunic ; a large pharyngeal chamber and a ventral heart present. 



Class I. Larvacea. Minute, free-swimming timicates with a long tail. 

 Ex. Appendicularia. 



Class 2. Thaliacea. Free-swimming, transparent tunica tes. Ex. Salpa. 



Class 3. Ascidiacea. Sessile, saccular tunicates, either shnple or colonial. 

 Ex. Molgula. 



SuBPHYLUM HI. Leptocardia. Elongated, fishHke chordates, compressed 

 laterally and attenuated at both ends. Ex. Amphioxus. 



SUBPHYLUM IV. Vertebrata. Chordates with distinct head, bearing 

 organs of special sense, with red blood, and usually with two pairs of 

 appendages. 



Class I. Pisces. Fishes. Aquatic vertebrates which breathe by means 

 of gills, and usually with bony scales and paired fins. Ex. Perca. 



Class 2. Amphibia. Amphibians. Vertebrates with giUs during a part 

 or all of their life, and usually with lungs ; scales mostly absent. Ex. Rana. 



Class 3. Reptilia. Reptiles. Vertebrates with body covered with horny 

 scales or plates and without gills. Ex. Coluber. 



Class 4. Aves. Birds. Feathered vertebrates whose anterior appendages 

 are wings. Ex. Callus. 



Class 5. Mammalia. Mammals. Hair-covered vertebrates which suckle 



their young. Ex. Felis. 



