CLASSIFICATION OF ACTINIARIA 263 



Genera : Myonanthus, Macrodactyla, Bolo- 

 ceroides, Nevadne. 



Myonanthus, McM., 1893, p. 151. 



Myonanthidae with smooth body and slight fosse within the margin. 

 Tentacles retractile, without sphincters. Sphincter definite, diffuse, and 

 may have a good deal of anastomosis between its processes. All mesen- 

 teries fertile save the directives and the youngest. 

 Species : 



M. ambiguus, McM., 1893, p. 151. 



Macrodactyla, Haddon, 1898, p. 431. 



Myonanthidae with a deUcate skin covered with little adhesive suckers. 

 Large suckers on upper part of body. Fragments may adhere to it. 

 No capitular rim or acrorhagi. Tentacles may be long and large, and are 

 without sphincters. Sphincter not strong, sessile, circumscribed diffuse. 

 Retractors strong, circumscribed diffuse. All mesenteries fertile. 



Species : 



M. aspera, H. and S., 1893, p. 124; Haddon, 1898, p. 431. 



There is a slight ambiguity in Haddon's definition of this 

 genus — 1 take his meaning to be that there are six pairs of 

 perfect mesenteries, but if by any chance it is otherwise the 

 genus will have to go to Actiniidae. 



BoLOCEROiDES, Carlgr., 1899, p. 43. 



Myonanthidae with smooth body and tentaculate margin. No 

 sphincter, no true siphonoglyphes, no basilar muscles. Ectoderm of 

 body-wall and actinopharynx has spirocysts and muscle fibres as well 

 as that of disc and tentacles. Tentacles provided with sphincters, there- 

 fore deciduous. All stronger mesenteries fertile save directives. 

 Species : 



B. McMurrichi, Kwiet., 1898, p. 394. (See also Carlgren, 1899, 



p. 43 ; 1900, p. 16.) 

 B. hermaphroditioa, Carlgr., 1900, p. 18. 



A discussion of the systematic position of this genus will be 

 found in Part II, p. 506, &c. 



Nevadne, n. gen. 



Gyrostoma as used by Annandale for G. glaucum 

 (1915, p. 70). 

 Myonanthidae. The one known form has longish body and long 

 NO. 262 XJ 



