PLATE IV. 



FIG. lar-ff. Hyalasctis hodgsoni. Spicules. (Page 4.) 



FIG. la. Autodermal hexactin. (x Kin.) 



FIG. li. Autodermal pentactin. (x 100.) 



FIG. Ic, c 1 , c 2 . Modified autodermalia. (x 160.) 



FIG. Id, Id 1 . Hypodermal oxypentactins. ( X 50.) 



FIG. Id-. Autogastral hexactin. (x 160.) 



FIG. le. Holoxyhexaster. ( X 240.) 



FIG. le 1 . Hemioxyhexaster. (X 240.) 



FIG. le 2 . Monoxyhexaster. (X _'4n.) 



FIG. I/. Holodiscohexaster. (x 24(i.) 



FIG. I/ 1 . The same (part), (x 700.) 



FIG. Iff. Microdiscokexaster. (Optic, sect.) ( x 700.) 



FIG. 2a-g. Rossella antarctica Carter. Spicules of Specimen A. (Page 6.) 



FIG. 2a. Parenchymal regular hexactin. (x 160.) 



FIG. 2b. Autodermal pentactin. (x 160.) 



FIG. 2ft 1 . Autodermal hexactin. (x 100.) 



FIG. 26 2 . Autodermal stauractin. ( x 160.) 



FIG. 2c. Autogastral hexactin. (x 160.) 



FIG. 2d, 3d 1 . Holoxyhexasters. (2tf l in optic, sect.) (x 160.) 



FlG. 2d 3 . Hemioxyhexaster. (x 160.) 



FIG. 2d 3 . Monoxyhexaster. (x 160.) 



FIG. 2d*. Central part of 2d 3 , showing termination of axial canals. ( X 700.) 



FIG. 2e. Hemidiscohexaster (modified), (x 700.) 



FlG. 2/. Calycocome. (Optic, sect.) ( X 700.) 



FIG. 2//. Portion of another calycocome with shorter smooth shaft and divergent rays, (x 700.) 



FIG. 2h. Microdiscohexaster. (Optic, sect.) ( x 700.) 



FIG. 3a-k. -Rossella antarctica. Spicules of Specimen C, only 3h being from Specimen B. (Page 8.) 



FIG. 3a, Sa l . Oxypentactin basalia. ( X 50.) 



FIG. 3i. Autodermal pentactin. (x 160.) 



FIG. 3e. Autogastral hexactin. ( X 160.) 



FIG. Sc 1 . Autogastral pentactin, a kind only found in Specimen C. (x 160.) 



FIG. 3d. Holoxyhexaster. (Optic, sect.) ( x 240.) 



FIG. 3d 1 , 3d 2 . Hemioxyhexasters. ( x 240.) 



FIG. 3d 3 , 3d*. Monoxyhexasters. ( x 240.) 



FIG. 3d 6 . Stauractin -like monoxyhexaster. ( x 240.) 



FIG. 3d 6 . Three spheroidal reduced oxyhexasters. (x 240.) 



FIG. 3e. Seven discohexasters, showing variation in form. ( X 240.) 



FIG. 3 l . Hemidiscohexaster. ( x 700.) 



FlG. 3f. Calycocome. (Optic, sect.) ( x 240.) 



FlG. 3/ 1 . The same (a part), (x 70<.) 



FlG. 3g. Part of another calycocome. ( X 700.) 



FIG. 3h. Abnormal calycocome, from Specimen B. ( x 700.) 



FIG. 3Jc. Microdiscohexaster. (Optic, sect.) ( x 700.) 



FIG. 31. Portion of a variety of microdiscohexaster. ( X 700.) 



