TUNICATA. 0^6 



SiDNYUM, Sav. 

 T?/pe, S. turbinatum, Sav. British coast. (F. and H. PI. A, B. fig. 2.) 

 Test gelatinous, iucrnsting ; systems numerous, conical, truncated and 



starred at" the summit ; tunicaries 5 or 6 to 10 or 12, forming a margin 



round a depressed centre; brancliial orifice 8 -toothed; vent simple, tubular; 



ovary pedunculate. 



Found on the under surfaces of shelving rocks, at low-water spring tides, 



formiug translucent amber-coloured masses. 



Amoroecium, M. Edw. 



Efi/}n. Amoiros incomplete, oikos house. 



Ei. A.' argus, PI. 24, fig. 17- A proliferum, (larva) fig. 18. 



Test fleshy or coriaceous, polymorphous, incrusting or,: slightly peduncu- 

 late ; systems numerous ; tunicaries grouped round common apertm-es ; 

 abdominal divisions indistinct. 



Distr. 4 sp. British Channel, IVIedit., Aegean. 



Suh-gemis Parascidium, M. Edw. P. flavum, 24, fig. 16. Oral openings 

 8-lobed, each accompanied by 2 oculiform points. 



Synoecium, Phipps, 1773. 



EUjm. Si/noil-os united house. Ti/pe, S. turgens, PL 24, fig. 19. 



Test semicartilaginous, cylindrical, pedunculate, isolated or gregarious ; 

 systems single, circular, terminal, tunicaries G — 9 ; branchial orifice 6-rayed, 

 anal of 6 unequal rays ; post-abdomen sessile. 



Divisioti I. Bistellate Polyclinians. 

 SiGILLINA, Sav. 



Etym. Sigilhim, a seal, Ex. S. Australis, PI. 24, fig. 20. 



Test gelatinous, solid, conical, elongated, pedunculate, solitary or grega- 

 rious; systems single, of many individuals, in irregular circles one above 

 another; orifices both 6-rayed ; abdomen larger than thorax ; post-abdomen 

 long and sleoder. 



FAMILY IV. Pyrosomid^. 



Animal compound, free, pelagic. 



Pyrosoma, Peron, 1804. 



Etym. Pi/r (pi/ros) fire, soma body. 



Ex. P. giganteum, PI. 24, fig. 21. 



Body cartilaginous, non-contractile, cylindrical, hollow, open at one end 

 onlv ; exterior covered by the numerous pointed zoids, grouped in whiris 

 interior mamillated and pierced by the exhalent orifices of the tunicaries. 



