384 WILSON. 
EXPLANATION OF PLATE XIV. 
(Zsperella fibrexilis.) 
Fic. 1. Esperella fibrexilis. <x 1%. 
Fic. 2. Vertical section of Esperella, showing canal system and skeleton. A.4. 
Fic. 3. Spicules. a, oxytylote; 4, modification of the same; c, after treatment 
with caustic potash; d, toxaspire; ¢, sigma; f, sigmaspire. D.4. 
Fic. 3’. a, 4, c, views of small shovels: a, somewhat from the end; 4, face 
view; ¢, side view. d,a small sigma which will develop into a shovel. X goo. 
Fic. 3”. Large shovels —a, face view; 4, side view; d./. dorsal lobe; v.2., 
ventral lobe; /.7. lateral notch; 4, tooth. X goo. 
Fic. 4. Dermal membrane. A.4. 
Fic. 5. Surface of adult. 4-inch objective. 
Fic. 6. Ditto, showing osculum and oscular cavity. 
Fic. 7. Surface of adult. 4-inch objective. 
Fic. 8. Section: gemmules in mesoderm of parent. X 8oo. 
Fic. 8’. Different conditions of the nucleus in the gemmule cells. 
