152 
G. HERBERT FOWLER. 
in the centre is the opening to the coelenteron, left on invagination of 
the oral disc; the dark ring surrounding it is produced by the inverted 
stomodseum, &c. ; and from this the true tentacles radiate outwards, 
among the mesenteries. X 30. 
Fig. 2. — The smallest specimen, expanded; viewed from the oral surface. 
Round the true tentacles (cf. note, p. 143) are seen the budding 
pseudo-tentacles. X 50. 
Fig. 3. — Diagram of a vertical section of the contracted polyp, from a 
camera lucida drawing, te. The true tentacles, ps. t. The pseudo- 
tentacles. st. The inverted stomodseum. mes. The mesenteries. 
X 30. 
Fig. 4. — Portion of the oral disc, showing three stages in the development 
of the pseudo-tentacles. X 47. 
Fig. 5. — Transverse section through the invaginated oral disc and stoma- 
todseum at the base of a tentacle in a contracted specimen. The arrow 
indicates the plane of section in Fig. 6. The pair of mesenteries ex- 
hibit the protractor exocoelic muscles in transverse section (compare 
their trend in Fig. 3). The laminated cuticle external to the ectoderm 
is probably only a mucous secretion, x 210. 
Fig. 6. — Vertical section through the invaginated oral disc and stomato- 
dseum, i.e. an enlargement of part of Fig. 3. The arrow indicates the 
plane of section in Fig. 5. X 210. 
Fig. 7. — Transverse section of normal mesenterial filament, x 210. 
Fig. 8. — Transverse section of (?) abnormal mesenterial filament, x 210. 
Fig. 9. — Section through the root of a pseudo-tentacle. The endoderm 
is completely obscured by zooxanthellse. The endodermal circular 
muscle of the wall of the body is well seen, x 210. 
Figs. 10 — 16. — Phialactis neglecta, gen. sp. nn. 
Fig. 10. — Lateral view of the polyp. X 3. 
Fig. 11. — Diagrammatic longitudinal section of the polyp, showing the 
position of the oral opening at the bottom of the cup. x 3. 
Fig. 12. — View of the cup from above. X 3. 
Fig. 13. — Schematic transverse section through the base of the oral 
cone. sph. Sphseridia. st. Stomodseum. m. Mesentery, x 32. 
Fig. 14. — Schematic transverse section through a part of the cup. 
sph. Sphseridium. or.d. Inner or oral disc surface. b.u>. Outer or 
body- wall surface, m. Mesentery, x 47. 
Fig. 15. — Transverse section of a mesentery (p. 150). X 62. 
Fig. 16. — Nematocyst of the larger kind, with cnidocil. X 210. 
