EXPLANATION OF PLATE LIIL 



Lettering — g, granules ; n, nuclei ; o, oil-globules ; v, spicules ; 

 X, Xanthellse. 



GoUozoum annatum, Haswell. A single zooid in optical section, x 

 450. 



CoUozoum alpha. A portion of the colony she\A"ing one of the 

 ordinary zooids and one of the masses of granule^like bodies 

 supposed to be niici-ospores. x 450. 



CoUozoum ovale, Haswell. A single zooid. x 300. 



GoUozoum arcuatum, Haswell. A single zooid with the peculiarly 

 modified XantheUre. The oil-globule has been here rendered 

 black. The amorphous pigmented masses within the capsule are 

 not represented, x 450, 



Eigs. 4a, 4b, 4c. XantheUce of CoUozoum arcuatum. x 900. 



Fig. 5. CoUozoum beta, A single zooid in optical section, showhig the layer 

 of minute bodies superficial to the capsular-membrane. x 300. 



Fig. 6. CoUofsphcera hedleyi, Haswell. Test of a zooid. x 300. 



Fig. 7. CoUosphara uiiiforis, Haswell. Test, x 300. 



