100 E. PERCIVAL 



Abbren^iatioxs. 



C.S., connecting strand. Cav., cavity of longitudinal muscle. Col.. 

 columella. £'c^, ectoderm. End., endo(\enn. ii'.i-.iJc^, exumbral ectoderm. 

 £'x.£'?irf., exumbral endoderm. 6'., gastral cavity. G-'.i*"., gastral filaments. 

 G.P., gastral pouch. Gr., groove of endoderra to form manubrium. 

 L.M., longitudinal muscle. Mn., manubrium. P., plug of endoderm 

 cells to form interradial portion of manubrium. P.P., peristomial pit. 

 R., rod of ectoderm cells to form peristomial pit of polyp. B.C., remnant 

 of exumbral end of columella after rupture. R.L.M., degenerate longitu- 

 dinal muscle. S., split in ectoderm and in endodermal plug. S.O., Septal 

 ostium. 



