PLATE XV. 



PAGE 



Fig. 1. Esperella mammiformis, suhtjlostylwii : x 180, . . . 63 



Fig. 2. Esperella lapidiformis, stylus ; x 75. . . . . .65 



Figs. 3, 3a. Esperella fusca, tylostjli ; x 180, . . . . .72 



Figs. 4, 4«. Esperella arewcWa, tylostyli : x 175, . . . . 73 



Fig. 5. Esperella mtda, tjlostyiua ; x 175, . . . . .71 



Fig. 6. Esperella porosa, tylostyluH ; x 180, . . . . .70 



Figs. 7,7a. Esperella simonis, suhtylostyli ; x 180, . . . . 74 



Fig. 8. Espei'ella biserialis, small tylostylus ; x 180, . . . . 75 

 Figs. 8a, 8b. Large styli from the stem ; x 78. 



Fig. 9. Esperella porosa, aigmat-A ; xl80, . . . . . 70 



Fig. 10. Esperella lapidiforrnis, Tpalmate eLmsochela, ivont view ; x 360, . 65 

 Fig. 10a. Palmate anisochela, side view ; x 360. 



Fig. 11. ^s^^ereZ/a nwrfa, palmate anisochelse, front and side views ; x 860, . 71 



Figs. 12, 12a. Esperella simonis, toxn; x 180, . . . . .74 



Fig. 12a. Shows the remains of the cell in whieb the spicule developed still adhering 

 to it. 



Fig. 13. Esperella simonis, sigma. ; x 180, . . . . .74 



Fig. 14. Esperella 7mda, nigmat-d : x 180, . . . . .71 



Fig. 15. As^ereiZa /i<A'ca, palmate anisochela, three-quarters front view ; x 360, 72 

 Fig. 15a. Palmate anisochela, side view ; x 360. 



Fig. 16. J^'spereiZa amio/MS, palmate anisochela, front view ; x 360, . . 74 



Fig. 16a. Palmate anisochela, side view ; x 360. 



Fig. 16?'. Palmate anisochela, small end, seen from in front, looking from the larger end. 



Fig. 1 6c. Young anisochela, front view ; x 360. 



Fig. 17. ii^spere/Za porosa, palmate anisochela, front view ; x 360, . . 70 



Fig. 18. ^spereZZa wiamm^/brm^s, palmate anisochela, front view ; x 360, . 63 

 Fig. 18a. Palmate anisochela, side view ; x 360. 



