304 W. WOODLAND. 
Fic. 6.—A young spicule placed end-on. The concentric lamellar structure 
of the organic axis shows well. 
Fig. 7.—An older stage of growth. 
Fires. 8—12.—-Various forms of adult spicules. 
PLATE 17. 
Fies. 13 and 14.—Various forms of adult spicules. 
Fig. 15.—Monaxon unbranclied spicules found in the vicinity of limiting 
layers. 
Fics. 16 and 17 show the mesoglceal cavities in which the spicules are 
situated. 
Fre. 18.—An “endodermal cord”’ with several multinucleated cells. 
Fie. 19.—Scleroblasts. 
Fic. 20.—Interstitial cells. 
Fie. 21.—Spherical “jelly-secreting”’ (Bourne) cells. 
Fic. 22.—Nematocysts (‘ovoid bodies”) from the mesoglcea situated 
some distance under the ectoderm. 
Fic. 23.—Nematocysts from the surface of the colony showing cnidocils. 
