PLATE XI. 
LETTERING ON THE FIGURES. 
col.w.,. . . . .- column wall. Mey - . . . . mesentery. 
¢. iS:, cell-islet. m. fil., . . . . mesenterial filament 
O Bx ciliated streak (Flimmerstreif). Mes, . - - = ~ mesoglea. 
Pon cuticle. mg. st., . . . . marginal stoma. 
d., directives. mr.m., . . . . Macrocnemic mesentery. 
dise, disc. nem., . . . . . mnematocyst. 
ect., ne eee CLOCLCITN: Wrolby 6 6 6 6 0 WON GIEn et 
ect.can., . . . . ectodermal canal. ob.m., . . . . . oblique muscle. 
ect.m., . . . . ectodermal muscle layer. p.b.m., . . . .  parieto-basilar muscle. 
ene. 8. . . . . encircling sinus. per. st., . . . . perioral stoma. 
Guth, 6 © endoderm. r. ect., - . . . reflected ectoderm. 
end.m., . . . . endodermal muscle layer. Tr. Ma, . . . . . retractor muscle. 
Ff the fibrillar layer. Po 8 0 0 0 © o waAnOIkIE engl 
Sos., fossa. $45) 4) 4) sulcardirectives: 
gl. c., gland cell. sl.d., . . . . . sulcular directives. 
9-9"). . . . . gonidial groove. Bin co 0 0 o o NCEA, 
JS, glandular streak. sph.m., . . . . sphincter muscle. 
(Driisenstreif, Nesseldriisenstreif), St... stomodzum. 
me., incrustations. tent, . . . . . tentacle. 
a. 8., intermediate streak. 200%., runes zooxanthelle. 
lac., lacune. I., Il., 1., &c., . . orders of mesenteries or tentacles. 
Figure 
1. Phymanthus crucifer. Transverse section through a portion of the column-wall and a mesen- 
2. 
3. 
4, 
5. 
6. 
7. 
8. 
tery of the first order, and one of the mesenteries of the fourth order, taken a little below 
the stomodeal region. x 820. 
Phymanthus crucifer. Transverse section through a trilobed mesenterial filament. x 320. 
Actinotryx Sancti-Thome. Vertical section through the upper region of the column-wall, showing 
the mesogleal plaitings for the support of the sphincter muscle. x 250. 
Actinotryx Sancti-Thome. Transverse section through a mesenterial filament, just below the 
stomodeal region. One of the large nematocysts is represented in longitudinal section and 
another in transverse section. x 250. 
Ricordea florida. Plan of tentacular arrangement. The members of the outermost cycle are in 
the same radial areas as the inner tentacles, and alternate with those of the next cycle 
within. The arrangement in orders is not very regular in larger polyps. 
Ricordea florida. Transverse section through the stomodel region to show the irregular arrange- 
ment of the mesenteries, and the columnar and stomodeal mesogleal processes. Only a 
few of the columnar processes are represented. x 12. 
Stotchactis helianthus. Plan of tentacular arrangement in a young specimen. The members 
of the outermost cycle communicate with the exocceles and alternate with all the radial rows, 
which are endoceelic. 
Actinoporus elegans. Plan of tentacular arrangement. 
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