60 



CHAPTER HI, 



SEA-FEATHERS, SEA-PENS, AND SEA-FROTH, — PENNATULA PHOSPHOREA. — 

 VIRGULARIA MIRABILIS. — PAVONARIA QUADRANGULARIS. — GORGONIA 

 VERRUCOSA. — kingfisher's NEST OR MERMAID'S GLOVES. — ALCTONIUM 

 DIGIT ATUM. — ALCYONIDIUM HIRSUTUM. — INFUSORIA AND FORAMINIFERA, 



The three families — TennatididcBy Gorgoniadce, Alcyoniadxe 

 — are included by Gosse in the sub-order Alcyonaria. The 

 family of Alci/oniadcej which contains Alcijonium digitatnm, 

 of which we shall speak presently, appears to partake much 

 of the nature of Sponge, only that the fleshy masses of 

 which it is composed, send forth distinct and beautiful 

 polypi. It differs from the other two families, Tennatididce 

 and Gorgoniadce, in not having, like them, a central axis ; but 

 instead of that axis, the flesh contains scattered calcareous 

 spicula, similar to those Sponges. 



In the Hydroid Zoophytes, it was observed that the horny 

 skeleton formed, as it were, a case, or external support to 



