THE ANTHOZOA 59 



FAMILY 1. GONACTINIDAE. Sulcus and sulculus present. Eight 

 Edwardsian macromesenteries and eight micromesenteries. The sulcar 

 and sulcular macromesenteries are sterile, the four remaining macro- 

 mesenteries are fertile, and form couples with four micromesenteries. Of 

 the four remaining micromesenteries there is a couple in each sulculo-lateral 

 chamber. Genus Gonactinia, Sars ; Gonactinia prolifera reproduces itself 

 asexually by strobilisation. FAMILY 2. ORACTIDAE. No sulculus. 

 Mesenteries as in Gonactinia, with an additional couple of micromesenteries 

 in the transverse chambers. Genus Oractis, M'Murrich. FAMILY 3. 

 MONAULIDAE. Sulculus absent. Fourteen tentacles and fourteen complete 

 mesenteries arranged as in Gonactinia, but the sulculo-laterals are absent. 

 Genus Scytophorus, Hertwig. 



GRADE II. CR YPTOPA RA MERA . 



Zoantharia in which the primary bilateral symmetry is obscured by 

 radial development of the second and succeeding cycles of mesenteries. 



ORDER 6. Actiniidea. 



Colonial or solitary Zoantharia cryptoparamera, with or without a 

 skeleton. Sulcus and sulculus both present (with rare exceptions). 

 Mesenteries arranged in cycles. Each cycle consisting usually of twelve 

 couples of equal size. Typically a couple of new mesenteries is formed 

 in each exocoele formed by previously existing cycles. The muscle 

 banners of the sulcar and sulcular directive mesenteries are turned away 

 from one another ; in all other couples they are vis a vis. Tentacles equal 

 in number to the mesenteries, one over each endocoele and exocoele. 



SUB-ORDER 1. MALACACTINIAE. Solitary Actiniidea or very rarely 

 forming colonies. Without a skeleton. 



GROUP A. HEXACTINIAE. 



FAMILY!. ILYANTHIDAE. Free Malacactiniae, not adhering by a basal 

 disc. Aboral end of body rounded. SUB -FAMILY HALCAMPINAE. 

 Tentacles twelve. Mesenteries twenty-four six couples complete, six 

 couples incomplete. Genus Halcampa, Gosse. SUB-FAMILY ILYAN- 

 THINAE. Genus Ilyanthus, Forbes. SUB-FAMILY PEACHIINAE. Ten- 

 tacles twelve. Mesenteries twenty ; six primary couples complete, fertile ; 

 four secondary couples, the sulculo-lateral couples being absent. A single 

 conchula present. Genus Peachia, Gosse. 



FAMILY 2. ACTINIDAE. Malacactiniae with an adherent basal disc. 

 Tentacles simple, uniform, arranged in cycles on periphery of peristome, 

 one tentacle over each exocoele and endocoele. SUB-FAMILY ANTHEINAE. 

 Marginal tubercles present. No circular muscle. No acontia. Genera 

 Actinia, Browne ; Ammonia, Risso ; Comactis, M. Edw. SUB-FAMILY 

 SAGARTINAE. Circular muscle present. Acontia present. Primary 

 mesenteries alone complete, and are sterile. Division A. Circular muscle 

 endodermal. Genus Actinoloba, Blainville. Division B. Circular muscle 



