1 14 Introduction to Animal Morplwlogy. 



China Sea they have been found up to three feet in 

 diameter, and containing Clupeoid fishes as com- 

 mensals (Collingwood}. 



Three families exist: i. Xoantlmkv the only colonial 

 forms, with a creeping, leathery, filiform, spiculigerous 

 coenosarc; /ooids united by a ilat, root-like mass of stolons 

 (Palythoa), or by basilar budding (Xoanthus). The tentacles 

 are in .several cycles, each one communicating with one 

 segment of the perivisceral cavity. Foreign bodies maybe 

 enclosed in the ccenosarc (Heterozoanthus). 



2. Ccriantlmke hermaphrodite ; with no spiculcs ; ten- 

 tacles in two conecntric circles, not alternate, two communi- 

 cating with each intermesenteric space. The mesenteries 

 do not extend to the hinder end, and in the young there are 

 onlv lour. The abural end is pointed, perforate Verianthus), 

 or imperf" In the former, two mesenteries 



extend farther than the others, and a deep, gutter-like groove 

 continues along its body cavity to its foot. It throws off a 

 slough of thread cells and mucus, mixed with foreign bodies. 







\ctiniida: separate persoiuv, with many series of ten- 

 'inach with two lateral grooves (cartilaginous in 

 Sphenopus). This includes four sub-families : Minyadina; 

 having the foot dilated into a rounded air-holding sac ; the 

 body may be warted (Minyas) or smooth, with simple 

 (Plotactis) or lobed tentacles (Nautactis). Actininoe foot 

 with a muscular sole (sucking disc) ; tentacles conical, 

 uniform, not retractile (Anthea) or retractile (Actinia). The 

 mouth may have two long lips (Actinopsis), or several crispate 

 lobes (Metridium), or a trifid lip (Siphonactinia). A few are 

 rounded, or pointed distally, and free swimming ; of these, 

 I'eachia and Ilalcacampa have a distal perforation. Milnea 

 and Araclmactis are rounded, and the former has a median 

 epidermic girdle; Ilyanthus is pointed, imperforate ; cinclides 

 are numerous, and often wart-like in Cribrina, Sagartia, 

 Adamsia, OMC. Phyllactinae tentacles both simple and lobate, 

 the latter in an outer cycle (Phyllactis), or between two - 

 of simple ones (Rhodactis). Ulactis has a warted body. 



