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COLLEGE ZOOLOGY 



This order includes the sea-fans which are to be found in 

 almost every museum, and the precious red coral (Corallium, 

 Fig. 89, C), which occurs in the Mediterranean and is widely 

 used in the manufacture of jewelry. 



Order 4. Pennatulacea. ALCYONARIA forming bilaterally 

 symmetrical colonies; zooids usually borne on branches of an 



FIG. 89. Coral. A, Tubipora musica, organ-pipe coral, a young colony. 

 Hp, connecting horizontal platforms; p, skeletal tubes of the zooids; St, 

 the basal stolon. B, Alcyonium digitatum, with some zooids expanded. C, 

 Corallium, a branch of precious coral. P, polyp. D, Pennatula sulcata, a sea- 

 feather. (A and B, from Cambridge Natural History; C, from Sedgwick, after 

 Lacaze Duthiers; D, from Sedgwick, after Kolliker.) 



axial stem, which is supported by a calcareous or horny skeleton. 

 Examples: Pennatula (Fig. 89, D), Renilla. The sea-pens 

 (Fig. 89, D) live with their stalks embedded in muddy or sandy 

 sea-bottoms. Many of them are phosphorescent. 



