^i OH the Natural Group of Tunicata. 553 



A. Anal orifice. 



C. Branchial orifice. 

 ^ E. Envelope. 



K. Right ovary, lying between stomach and bran- 

 chial pouch. 



d. Oviduct of same, opening towards anal orifice. 



k. Left ovary, terminating upwards in a neck. 



O. (Esophagus, or that extremity of the intestinal 

 canal which communicates with the branchial 

 pouch. 



S. Stomach. 



H. Anus. 



V. Heart. 



D. Dorsal sulcus. 



0. Lateral orifice, communicating by a tube t, with 

 a diaphanous pouch p, containing one or two 

 blackish nodules n. 

 Fig. 4. Cystingia Griffitlmi much magnified as before, but having 

 the whole of the right side of the envelope removed, and 

 the stomach thrown further back, in order to show the 

 branchial pouch, which appears communicating by a 

 narrow neck with the branchial orifice. The left ovary 

 is hid by the enormous stomach, but in other respects 

 the parts are nearly in the same situation as in the former 

 figure. 

 Fig. 5. Heart of Cystingia Griffithsii (magnified), having the se- 

 cond of its four vertical apertures stretched open. 

 Fig. 6. The heart and other parts on the right side of Cystingia 

 Griffithsii lifted up, to show the oviduct of the left ovary 

 opening downwards to the anal orifice, round which we 

 observe a net-work of muscular fibres reticulating on the 

 mantle. 



Tab. 



