243 



n. sp., but ill M. rra.9sa, Wright and Studer, the end is occupied by three polyps 

 — the terminal expression of a spiral arrangement. 



(e) Verruca'. — The verrucas are mostly sub-conical, but in M. perramosa, 

 Wright and Studer, they are hemispherical, and in M. arborea, n. sp., they are 

 cylindrical with a terminal dome ; and while those of the twigs of M. ramosa, 

 Thomson and Henderson, are typical, those of the main stem and branches are 

 small and wart-like. They generally stand at right angles to the axis and are 

 sometimes flattened in the plane of ramification, e.g., M. rubra, Thomson, and 

 also markedly elongated in the direction of the axis, e.g., M. purpurea, White- 

 legge, and M. rubra, Thomson, var. robusta. The armature consists of spicules 

 similar to those of the ccenenchyma, but smaller and arranged for the most part 

 longitudinally. In M. nitida, Verrill, they are upi'ight or obli(j[ue ; in M. teiwra, 

 KidJey, they are upright or transverse; in M. purpurea, Whitelegge, they 

 are in eight indistinct bundles, while in M. crassa, Wright and Studer, they 

 are in eight bands of two rows. In the majority, however, they are dis- 

 posed in eight groups with eight projecting teeth, e.g., M. perramosa, Wright 

 and Studer, M. nnnplanata, Wright and Studer, M. ramom, Thomson and 

 Henderson, etc., while in M. arborea, n. sp., near the base they are transverse 

 but higher up in eight bands of pairs " en chevron," the angle gradually di- 

 minishing until generally a single pair projects from each band at the margin. 



(/) Anthoeodice. — The anthocodite are completely retractile and there is 

 generally a fairly definite tentacular operculum which, however, is hidden when 

 the verructe are closed. The operculum con.sists of a "crown" and "points" 

 but the number and arrangement of the spicules varies in the different species. 

 In M. perramosa, AVright and Studer, and M. crassa, Wright and Studer, it is 

 very poorly developed, in the latter consisting of a single pair on each tentacle ; 

 in M. complanata, Wright and Studer, the " crown " or collaret is very indefinite ; 

 in M. gracilis, Wright and Studer, it is almost horizontal and consists of two or 

 three spicules on the tentacles ; in M. bengalensis, Thomson and Henderson, 

 the collaret consists of one or two rows with a pair on each tentacle ; it is fairly 

 definite in M. tenera, Ridley, and well developed in M. nitida, Verrill ; in M. 

 rubra, Thomson, the collaret consists of two or three rows with four pairs " en 

 chevron " at the base of each tentacle, and in M. ramosa, Thomson and Hender- 

 son, it is high and dome-like with five rows in the collaret and eight pairs " en 

 chevron " on the tentacles ; in M. arborea, n. sp., there is no definite " crown 

 and points," but there are abundant spicules on the aboral surface of the 

 tentacles. In addition to an operculum, spicules arranged longitudinally occur 

 on the aboral surface of the tentacles in many species. 



(jj) Spicules. — These are typically warty spindles, straight, curved or S- 

 shaped. In some, e.g., M. tenera, Ridley, they are densely covered with papillose 

 warts, but in M. flexilis, Hiles, the warts are few and more or less rounded. 



