Plate VII. 



Regadrella olcinofieana Ij. 



Fig. 1. A complete and well-preserved specimen in the Sei. Coll. Mns. 

 72 nat. size. 



Fig. 2. A specimen without tlie upper end, bisected and seen from tlie 

 gastral side, -/s nat. size. 



Fig. 3. Dead skeleton consisting of fused spicules. ^/.. nat, size. 



Fig. 4. Same of small size. Nat. size. 



Fig. 5. Portion of a dead skeleton, with 3 very young specimens of the same 

 species attached to it. V/,, x . 



Figs. 6, 7. Two young specimens with still simple terminal osculum and with 

 parietal oscula beginning to open through. Nat. size. 



Fig. 8. Pentactin-dermalia from a very young specimen, such as one of 

 those shown in fig. 5. 1.50 x . 



Fig. 9. Immature floricome from a young specimen. 300 x . 



Fig. 10. Surface view of dermal layer from a very young specimen, con- 

 sisting of pentactin-dermalia. Here and there, rhaphidial sheaves. 

 50 X. 



Fig. 11. Spiculation as seen in cross-section of the wall of a very young 

 specimen with pentactin-dermalia. Above, the dermal surface ; 

 graphiocomes, sheaves of rhaphides, &c. 50 x . 



Fig. 12. Spiculation of the wall (peripheral portion only) of a small speci- 

 men, in which hexactin-dermalia have been added in large numbers 

 to i^entactin-dermalia of an earlier developmental stage. 50 X . 



