Plate XVIII. 



Page 

 Fig. I. Hamacaiitha Boiuerbaiiki n. sp. a styli, h developmental forms, x 165, c diancistra 

 of the largest form, d a series of developmental forms, x 380, e diancistra of 

 the middle form, f a developmental form, x 700, g the same diancistron, x 380 

 (b)- this enlargement the edges are not seen), h diancistra of the smallest 

 form, X 700, / the same diancistron, x 380, the edges are not seen, k toxa, 

 X380 99 



— 2. Haiiiaca7itha Bozverbaiiki n. sp. Dermal membrane with skeleton and projecting 



spicules, X 58 — 



— 3. Hamacantha Bozverbaiik/ n. sp. Radial section of the skeleton from the surface 



inward, x 32. a the skin with spicules — 







