180 MADEEPOEARIA. 



«. Var. cespitosa. 



This variety diflPers little from the form already described excepting in habit. The 

 specimens consist of small cespitose clumps 6*5 cm. high and 6 to 8 cm. broad ; branches 

 numerous and very crowded, each similar to one of the branchlets in form A. Immersed 

 corallites small and not numerous. 



/3. Var. 



Corallum spreading arborescent, 24 cm. high and 27 cm. broad. Branches curved and 

 very spreading, sometimes 18 cm. long and about 1'5 cm. thick, gradually tapering. They 

 bear numerous branchlets at an acute angle, which vary from elongate proliferous corallites to 

 7 cm. in length, all are under 1 cm. in thickness, and the majority are about 1'5 cm. long. 

 Radial corallites nearly all tubular, but the shorter ones are nariform ; a large number are very 

 spreading, about 5 mm. long, and bear two or three bud-corallites ; the others are shorter 

 and less spreading and many are subimmersed, but the truly immersed type is not frequent. 

 The star consists of 12 septa, well developed excepting in the short and inamersed corallites. 



B. Forma pygmsea. 



Colony erect arborescent ; stem 1 cm. thick, a little divided. Branchlets 1 to 3 cm. 

 long, but chiefly under 2 cm., and 3 to 5 mm. thick ; axial corallites not over 2 mm. diameter, 

 with a star consisting of 6 septa only. Radial corallites very variable in length and shape; 

 the short ones are nariform, sometimes compressed, and there are various intermediate forms 

 through dimidiate to tubiform. The diameter varies from 1 to 2 mm., the length from 

 1 to 3 mm.; the longer ones bear bud-corallites. The wall varies considerably in thickness, 

 often rather thin and only showing a thickness proportionate to that of other varieties in 

 the tubular corallites. Immersed corallites practically absent, their place being taken, 

 on the stems and branches, by appressed nariform or tubular ones. Surface of the 

 coenenchyma as in the other varieties, but the wall of the corallites near the apex of the colony 

 is substriate. 



This is the form recorded by Quelch, and all the ' Challenger ' specimens belong to it. It 

 differs chiefly in the more slender branchlets, the much smaller corallites, and the absence 

 of immersed corallites. 



C. Forma dumosa. (Plate XVI. fig. A.) 



Habit similar to that of var. pygmtBa, but more bushy, and the twigs are more acuminate. 

 The colony may be 21 cm. high and 20 cm. broad, the upper 12 cm. consisting of a new 

 incrustation over a dead colony. Near the base the branchlets often consist of a thick 

 tapering axial corallite, with scarcely open buds to within 9 or 6 mm. of the apex only ; 

 diameter at the apex 1"6 mm., diameter 9 mm. below that point (where the last bud is 

 situated) 23 mm. ; margin rounded, aperture scarcely recognizable. Nearer the apex of the 

 colony the axial corallites bear buds to within 2 or 3 mm. of the margin, which is then not so 



