THE CHORD ATES 385 



IncurrerA 



Oral -tenta-dc 



rNeural alamd 



ExCurrcnt 

 siphon. 



"Atrium. 



Intestine 

 Gon.ci.cL 



Heart 



.Genital duct 

 Esopha-^uS 



Digestive 



gizLn-d. 



S'bomsLCti. 



Otolith- 



Tncurrent 

 openin6- 



Sznsory vesicle 

 I— Ocellus 



Ex-currcnt opening 



r- Nerve cord 



Adhesive 

 pa.pilla. 



'Pharynx — 

 Endostyle 



Heart 



■Gill slii 

 "Atrium. 



'"Not o chord 

 -Strand of enioAerm. 

 '^Stomach. 



B 



Figure 20 7. Diagrammatic lateral views of an adult, -^ and a l-^^l'/^'^^f;,^^^^^^^ 



are embedded in the mantle. 



along the Atlantic coast. Other classes of tunicates, the Larvacea and 



the Thaliacea, are pelagic. enclosed 



A solitary adult ascidian is a sac-shaped creature that ^ en^losea 



in a leather/ tunic, which has been secreted by the -d- Ytng ^^^^ 

 wall, or mantle (Fig. 20.2, A). A considerable -^^^^J'^l^^^^^^^ 

 complex carbohydrate characteristic of the cell walls of plants but rarely 



