18 KERATOISIDJ3. 







7 inches across. The lower part of the main stem has a diameter of 

 three tenths of an inch in length. The branches are broken away 

 from this part of the stem ; but there are remains to show that some 

 of the inter] oints bore four branches, others only one. A cell, with 

 its marginal spines, measures the fifth of an inch." Johnson, I. c. 



39. EaUISETELLA. 



Coral erect, with whorls (?) of elongated, simple, jointed branches. 

 Bark and polype-cells unknown. 



97. Equisetella Gregorii, B.M. 



Stem thick, erect (?) ; branches verticillate (?), very long, slender, 

 filiform, with elongate, slender, smooth joints ; horny articulations 

 short. 



Isis Gregorii, Gray, Ann. $ Mac/. Nat. Hist.IS68, ii. p. 263. 



Hob. Japan. 



The branch in the British Museum is 26 inches long. 



Fam. 11. KERATOISID^E. 



Coral branched, tree-like, dichotomous ; branches cylindrical. 

 Bark thick, formed of abundant, longitudinally placed, elongate 

 fusiform spicules. Polype-cells subcylindrical, wider at top, covered 

 with spicules, and with eight or ten long spicules on the edge. Polypes 

 retractile. The axis, calcareous joints long, smooth, the cartila- 

 ginous short. 



40. KERATOISIS. 



" Polypidom branched ; axis of the stem and branches consisting 

 of nodes and internodes, the former stony, the latter horny ; the 

 stony joints vary from \ to 1 inch in length ; the branches rise from 

 the stony nodes, are not numerous, and present rather a straggling 

 appearance. The axis is covered with a barky layer, around which 

 the polypes arise ; this layer is studded over with numerous large 

 fusiform spicules, which completely cover the ectodermic layer of the 

 polypes. Eight or ten large spicules (about \ inch each in length) 

 form a circle around each polype ; these spicules are fusiform. Colour, 

 when fresh, a light pink." 



Keratoisis, Perceval Wright, in Ann, $ Mag. Nat. Hist. 1868, ii. p. 427, 

 1869, iii. p. 24. 



The spicules of the bark not warty but smooth, those surrounding 

 the cells upon the polypes of great length. 



