Plate XII. 



Äcantliascus cactus F. E. !Sch. P. 140. 



Fig. 23. StcUiractinic dermalia iu lateral view. 300 x . 



Fig. 24. Peiitactinic gastralia in lateral view. 300 x . 



Fig. 25. Perii)heral discoctastcr. 300 x . 



Fig. 26. IMicrodiscohexaster. 300 x . 



Fig. 27. üiscoctaster from siibgastral region. 300 x . 



Fig. 28. End of a terminal of a subga.stral discoctaster. Very highly 



magnified. 

 Fig. 29. Oxyhexaster, in which each nearly atrophied princi})al seems to 



bear two terminals. 300 x . 

 Fig. 30. Hemihexactinose oxyhexaster. 300 x . 

 Fig. 31. Hexactinose oxyhexaster. 300 x. 

 Fig. 32. Oxyhexaster with four terminals to each princii)al. A rare Ibrnj. 



300 X . 

 Fig. 33. Abnormal oxyhexaster, only once met with. 300 x . 

 Fig. 34. Ectosome in surface-view, sliowing the dermal lacework, the 



hy[)odermal strands and the perforated dermal membrane. The 



larger black dots in the last represent deei»ly stained thesucytes. 



About 4.") X . 

 Fig. 3."). End(^some in surface-view, showing the perforated gastral membrane 



and the various s[)icules found in and below it. J31ack dots as 



in last figure. About 4.3 x , 

 Fig. 3(i. Ends of parenchymalia of various sizes. 100 x . 

 Fig. 37. fSmall portion of basidictyonal framework. 100 x . 



