Plate XIII. 



Staurocalz/iAus affinis u. s}). 1*. 180. 



Ail lignres from Sei. Coll. I\lus. Sp. No. lî)4. 



Fig. 1. Exteriuil surface of the wall. Dermal spicules wautiug in iJie 

 greater part. Nat. size. 



Fig. 2. Uastral surface of the same. Canalar apertures mustly freely 

 open hut some covered with small-meshecl endosomal lattice 

 which is (lilferentiated in irregular jjatches. Nat. size. 



Fig. 3. Dermalia. ."jOO x . 



Fig. 4. Gastralia. 300 x . 



Fig. 5. Small discoctaster from subdermal space ; imperfectly develu})ed in 

 so far as some terminals remain isolated from the secondary 

 principals. 300 x . 



Part of a larger discoctaster from the subgastral space. 300 x . 

 iiexactinose oxyhexaster from choanosome. 300 x . 

 Microdiscohexaster. 



Fig. 9. Smooth-rayed oxyhexaster from eudosome. 300 x . 



Fig. 10. Small ])ortion of ectosome in surface view. JJermalia ami hypo- 

 dermalia held together l)y desiccated soft tissue. (]0 x , 



Fig. 11. Small jiortion of endosome in surface view. GO x. 



Fig. 12. Peri[)heral ]K)rtion of a section through the wall. Above, der- 

 mal surface. To the right, a group of paratropal hy[)oderiiial 

 pentactins. In the center, tlie central jjortion of a huge 

 parenchymal principalia, surrounded by comitalia. 30 x . 



Fig. 13. I'ortion adjoining the gastral surface; of a section thnaigh the 

 wall, ßelow, the gastral surface. 30 X . 



