12 G. HERBERT FOWLER. 



the corallum that the costae project through it^ and the exact 

 conditions are difficult to determine with certainty. 



B. Anatomy. — The general anatomy of the colony, as regards 

 the relations of canals, body wall, polyp cavities, &c., agrees 

 with that of M. Durvillei. Beyond the fact that in M. 

 as per a the polyp cavities are placed closer together, and that 

 therefore there are fewer canals in the corallum, there is little 

 or no difference between them. As regards the polyps, how- 

 ever, there is no dimorphism; all the polyps, except those 

 which are obviously immature buds, are identical in structure. 



A typical polyp possesses twelve perfectly normal mesen- 

 teries, and a stomatodseum which is a simple invagination of 

 the external body wall. When numbered on the same system 

 as in M. Durvillei, it is found that those mesenteries marked 

 1, 2, 4, 6, 7, 9, 11, 12, are the ones which develop mesen- 

 terial filaments, that is, the same mesenteries as in M. 

 Durvillei, with the addition of the abaxial "directives;" 

 while the others, 3, 5, 8, 10, generally have no filament, and 

 do not extend to the bottom of the stomatodaeum. 



The apical polyps are about twice the size of the others, 

 but, except for their possession of more septa, are identical 

 in structure with them. 



The muscles in both apical and lateral polyps are arranged 

 on the mesenteries just as in Actinia, and present nothing 

 unusual in structure. 



Tentacles I was unable to recognise, macroscopically or 

 by sections, but a figure by Dana shows that they are present, 

 and twelve in number. In this, as in the species last described, 

 they have shrunk into insignificance, owing to the action of 

 the spirit in which the specimens were preserved. They agree 

 with M. variabilis, in which, according to v. Koch, they are 

 also exocoelic and entocoelic. 



The histology calls for no remark, agreeing with that of 

 forms already described. Calycoblasts were very distinctly 

 present in the growing parts of the colony. 



c. Method of Budding. — With regard to this, I have been 

 able to gl6an but little information ; since the immature polyps 



