446 



CIIORDATA 



CviUliij.'-' !N[oi.c.ri IP.F, oral opening, six-lobed, airial foiir-lobed. }ro!i;iihi* 

 K:i:;yr,::' Sub Oixlcr II. S\ XASCIl'LK. Coinpound ascidians consisling 

 of numerous small individuals imbedded in a eommon tunie. Usually ^lii;. 502) 

 the indi\iduals of a eolon\' are di\ided into small groups, the oral openings of a 

 groui) forming a rosette around a eommon central atrium. Dislaplia,'^ Lcpto- 



FiC'. 500. — ^)e^"e]oylment of an Ascidian (after KuplTcr and Ko\\"ali: 

 larva, just hatchcil; 2, eross-section through the tail of a shghtly younger lar^■a; 

 younger stage, formation of notoehord and nervous system; 4. anterior end of 

 just before attaehment. (r, PJidllusui moilula: ;, 4, iV;. iiiiiminUhjIti .) ,111. 

 notoehord; f/. tiniie; (/. digesti\-e traet; </', its niUriti\"e, (/'', its respirat(^r\' (h\i 

 atrial \esiele; ck. eetoderm; rn, entoderm; //, brain; /. oral in\"agination; in, nui 

 tail; II, neural lube; hi', ncurentcrie eanal; 0, otoe^st; p, adhesive proeesses 



.4 B 



.''■ I. 

 . mil eh 

 a lar\-a 

 eye; r, 

 sion; (', 

 sell's of 



Fig. 501. Tig. 50-. 



Fig. 501. — .1. }{o!:;iiIli iihuilhillcmiy'': i'. Fji^vni /i///H/,jr/,\'* (from W-rrilO. 

 l-"iG. I 50J. — I'H'li-vlhci -'/e/wrrKv (after (.'arjH'Mlerb .1, small eolony of eighteen 

 individual groups; B, two individual group.^ somewhat enlarged. 



dinuiur Pfllytiiiuiiii/'' Amaroitciiiiiir Folrvlliis.''' Sub Order ITI. LUCT.T",. 

 Frce-s\vininiing pelagie synascidians, lia\ ing (he fo';rn of a hollow cylinder closed 

 at one end; the animals \erlic;il to the a.xis of the evlinder, oral ajx'rtures oil 

 the outside, atrial in the central cavity, ryrosoiiia, very phosphorescent, 

 tropical, some species four feet long. 



