248 T. A. STEPHENSON 



(and probably Oractis) only, not in the wider sense of Carl- 

 gron's later work. 



Aetiniaria witli or without a definite base, but without basilar muscles. 

 The body is smooth. There is a sheet of longitudinal muscle-fibres in 

 the ectoderm of body-wall and actinopharynx as well as of disc and 

 tentacles, and the body-wall ectoderm at least has also spirocysts. 

 iSpliincter absent or weak diffuse endodermal. Tentacles few or more 

 numerous, simple. In normal animals only eight mesenteries arc peiiect, 

 and these are the analogues of the eight macrocnemes of Edwardsia. 

 The mesenterial muscle is weak, often hardly more developed than the 

 body-wall muscle, and not forming a very definite retractor usually. 

 The number of mesenteries present beyond the eight protocnemes 

 varies, but the eight are not shaij)ly marked ofl fiom the others as 

 macrocnemes, although they have a certain predominance, especially 

 in Oraetis. l<\)ur imperfect mesenteries pair wnth the lateral proto- 

 cnemes, and the i-est form a secondary cycle or C3^eles. The distribution 

 of gonad and filament may alTect the protocnemes only (Oractis), 

 or the protoeneTues and their lateral partners (G onact inia), or the 

 whole of cycle 2 as well (Protanthea). The filaments have no ciliated 

 tracts. There are no well-marked siphonoglyphes. 



Family 1. Gonacttniidae, Carlgr., 1803. 



Used here sensn stricto for Gonac t i ni a , Protan- 

 thea, and Oractis only. 

 With the characters of the tribe Protantheae. 



GoN ACTINIA, Sars, 1851, p. 1 12. 



Gonaetiniidae with the gonads confined to the lateral protocnemes 

 normally, whereas the filaments are found not only on these but also 

 on their partners and on the directives. There is a definite ba.se. Repro- 

 duction often asexual. 



Species : 



G. prolifera. Sars. 18.35. p. 3. (8ee Carlgren. 1893. p. 31.) 



Protanthea, Carlgr., ]S*)1. 



Gonaetiniidae with gonads and filaments on the mesenteries of 

 cycles 1 and 2. and heytmd these cycles small mesenteries devoid of 

 appendages and confinod to the uppermost parts of the body. There is 

 a definite base. 



tSpecies : 



P. simplex, Carlgr.. 1891. p. 81 ; 1893 p. 24. 



