ACTINI2E EROM THE HERGUI ARCHIPELAGO. 



251 



mentioned Sagartid. It is now recognized that determinations 

 of Actiniae made from purely superficial characters are apt to be 

 erroneous ; so that a minute anatomical investigation of many of 

 the previously described forms is now necessary before they can 

 be confidently relegated to any group of the Actiniae. 



Dr. K. Hertwig divides the Actiniaria or Malaeodermata, in 

 his ' Challenger ' Keport, into six tribes. From the arrangement 

 of its mesenteries, Myriactis tubicola belongs to the first tribe, 

 the Hexactiniae. Nine families are enumerated as belonging to 

 this tribe. The first (Corallimorphidae) has accessory tentacles, 

 the last (Ilyanthidae) has a vesicular physa. The Tealidae have a 

 very strong endodermal circular muscle; while the Paractidae, 

 Liponemidae, Sagartidae, and Amphianthidae have a mesodermal 

 circular muscle. The Antheomorphidae are characterized by 

 possessing a " slightly developed muscular system, long, slightly 

 contractile tentacles, without any circular muscles (tentacles con- 

 sequently non-retractile) ; reproductive organs present on all 

 the septa [mesenteries] ; accessory tentacles wanting.'* Lastly, 

 the Antheadae are defined as " Hexactiniae with long marginal 

 tentacles and slightly developed endodermal circular muscle (so 

 that the oral disk cannot be covered at all, or only incompletely); 

 numerous septa, reaching for the most part up to the oesophagus, 

 distinguished only by their size, and all (?) furnished with 

 reproductive organs." 



On comparing the above descriptions with the definition of the 

 genus Myriactis, it will be seen that the latter cannot be placed 

 in any of these families unless one or more of their characters 

 are amended. Its exact systematic position must be left until 

 we have a more accurate knowledge of the tropical Sea- 

 Anemones. 



Hormathia Anderscxnt, n. sp. (Plate XX.) 



Form. Base expanded ; scapus leathery, with transverse 

 furrows, terminating above in twelve fairly regular bosses, which 

 are prolonged along the inverted capitulum as twelve prominent 

 ridges. Tentacles moderately long, pointed, arranged in four (?) 

 cycles, about 100 in number. 



Colour. Cuticle l^urnt sienna, speckled with grains of sand; 

 where the cuticle is rubbed off, the supporting tissue (mesoglcea 

 or " mesoderm ") of the scapus is yellowish ; terminal prominences 



