PLATE II. 



PAGE 



Fragments and isolated spicules of the macerated skeleton of Euplectella 



aspergillum, Owen, . . . .64 



Fig. 1. Isolated spicules from round about the parietal aperture of a young- 

 specimen ; X 50. 



Fig. la. Hexact with one shortened and rounded ra}'. 

 Fig. lb. Hexact with six almost equally developed rays. 

 Fig. Ic. Pentact with one somewhat elongated tangential ray. 



Fig. 2. Fragment of the connected skeletal framework of the lateral wall of a 

 young specimen, seen from the inside ; x 10. 



Fig. 3. Incipient union of two beams by means of sjmapticula ; x 100. 



Fig. 4. The larger portion of a triact from ii, young form ; x 50. 



Fig. 5. Fragment of the skeleton of the lateral wall of a young form, round about 

 a parietal aperture, seen from the interior ; x 1 0. 



Fig. 6. Fragment of the skeleton of the lateral wall of a young specimen ; x 50. 



Fig. 7. Fragment of the skeleton of the lateral wall of an adult form ; x 50. 



Fig. 8. Fragment of the connected skeleton of the lateral wall of an older 

 specimen, viewed from the outside ; x 10. 



Fifi'. 9. Portion of a floricome ; x 500. 



Fig. 10. Fragment of the connected skeleton from the margin of the terminal 

 sieve-plate and surrounding ledge ; x 1 0. 



This plate was executed under Sir Wyville Thomson's direction. 



