2 G. HERBEET FOWLER. 



Branchlets small and short, about 1 — 2 cm. in length, con- 

 sisting generally of a few thin and long tubiform calicles ; 

 towards the apical parts of the branches they become much 

 less elongated and often quite short. Surface slightly 

 porous, very distinctly costulated throughout, and marked with 

 fine echinulations which are very distinctly arranged on the 

 calicles. Calicles generally tubiform, about 1'5 mm. wide 

 and 1* cm. long, except towards the apical parts of the branches, 

 where they are shorter and smaller, and sometimes tubo- 

 nariform ; a few short tubonariform calicles are generally 

 placed on the surface of the branches between the branchlets. 

 Star distinct, of six more or less lamelli-spiniform septa, two 

 of which, the distal and the proximal, are usually much 

 enlarged, and meet one another, often deep down in the fossa; 

 while occasionally, as in the terminal calicles, the six septa are 

 subequal, and coalesce at the centre." 



" This species seems to be distinguishable from the M. 

 echinata (Dana) simply by the costulations of the surface, 

 which in the latter is smooth or finely granulated. It is 

 doubtful, however, whether this character will prove to be 

 sufficiently constant to separate the two species, when a larger 

 number of forms has been examined." 



Figs. 1 and 2 represent the dorsal and ventral aspects of a 

 fragment of a branch, and show most of the characteristics 

 mentioned in the above description. 



In a transverse section of the corallum (fig. 3), the peri- 

 pheral ring of polyp cavities is cut somewhat obliquely {a a.), 

 owing to the inclination of branchlets and calicles to the 

 branch ; while the more central ones, cut at a lower level and 

 more transversely, are approximately circular in outline («' 

 a'.). They lie, roughly speaking, on three sides of the branch, 

 none are apparent on the fourth. The shorter radius of the 

 latter seems to imply that the growth in diameter of the 

 branch depends upon the outward growth of the polyps. 



In the axis of the branch is a central cavity {c. c), into 

 which project six septum-like ridges ; this probably represents 

 a cavity previously inhabited by the now apical polyp. The 



