18 KERATOISID.E. 



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 interjoints 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 unkijown. 



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. Sf Mag. Nat. Hist. 1868, ii. p. 26.3. 



Hah. Japan. 



The branch in the British Museum is 26 inches long. 



Fam. 11. KERATOISIDtE. 



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

 Bark thick, formed of abundant, longitudinally placed, elongate 

 fusiform spicules. Polype-ceUs 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. KEEATOISIS. 



" 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 -L 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. 8f 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. 



