204 T. A. STEPHENSON 



Family 12. Actinodendriuae. 



Actinoflendridao, Haddon, 1898, p. 488 ; Carlgren, 1900, 

 p. 96. 



Aeremodactylidao, Dendrianthidae, Kwiet., 1897-8. 



Endomyaria with definite base, not always well marked off from the 

 coliunn, and it may be small. Smooth wall. No special margin. No 

 sphincter or a slight diffuse one. Disc produced into permanent arm- 

 like lobes, which are arranged in cycles like large tentacles, each bearing 

 numerous tentacles or branches on it (see Part II, Text-fig. 14, K) ; these 

 tentacles may be arranged all round the lobes or be more or less absent 

 from parts of them, and may bo themselves simple or immched, and in 

 the latter case giving the whole arm a dendritic effect (see Part II. 

 Text-fig. 10). Mesenteries all (or twelve pairs only perfect) perfect 

 and fertile, except sometimes the directives, with strong retractors. 

 Radial mustnilature of disc and tentacles ectodermal. There may be 

 concentrations of nematocysts in the tentacle-lips, in little thickenings. 

 The discal arms correspond one to each endocoel in the inner cycles, 

 on(i to each exocoel in the outer, the size varying according to cycle. 



Genera : A c t i n o d e n d r o n , A e < i n o s i (> p li a n u s , 



M e g a 1 a c t i s . 



Actinodendron, JMaiiiv., 1H30, p. 287. 

 Acremodactyla, Kwiet., 1S9S. 



Actinodendridae in which the tentacles are arranged all roiuid the 

 arms, and are themselves branched, and may have nematocystic 

 thickenings at their tips. Very strong diffuse retractors. (See Part II, 

 Text-fig. 19, for appearance of A, plumosum.) 

 Species : 



A. plumosum, Haddon, 1898, p. 490. (See Saville Kent, 1893.) 

 A . g 1 o m e r a t u m , Haddon, 1898. p. 492. (See Saville Kent, 1 893 



and 1897.) 

 A. hansingorum, Carlgi-., 1900. p. 98. 



A. ambonensis, Kwiet.. 1898, p. 401. (See Carlgi-en, 1900. 

 p. 96.) 

 And probably others. 



AcTiNOSTEPHANus, Kwiet., 1898, p. 40B. 



Actinodendiidae in which the tentacles are irregularly arranged on 

 the arms and are simple. Strong retractors. 

 Species : 



A. haeckeli, Kwiet., 1898, p. 403. 



