22 Coelenterata. 



outgrowths, generally in a single cycle, provided here and there with closely 

 apposed and very large nematocysts, a condition which indicates that the out- 

 growths are probably partly Randsackchen. This n. gen. is differentiated 

 from Asteractis and Cradactis by the presence of these Randsackchen and 

 by its diffuse sphincter. 



Wilsmore describes new Hexactinise from New South Wales. The endodermic 

 musculature of Peachia hilli is well developed, and is strengthened locally 

 in both the capitulum and the lower part of the scapus. It reaches its maximum 

 strength in the portion of the scapus adjacent to the physa. Probably the 

 presence of these muscles enables the animal to bore into the sand with its 

 physa. The sphincter is represented by an increase in the strength of the 

 endodermal muscle-plaitings in the capitular region. A single very large siphono- 

 glyph is present. There are numerous pores situated in longitudinal rows in 

 the body wall in the region of the physa. These are the openings of canals 

 which lead from the ccelenteron to the exterior. The ectodermic part of the 

 canal is much shorter than the endodermic part. A larval specimen had 12 ten- 

 tacles and 12 perfect mesenteries, of which the 8 primitive Edwardsian mesen- 

 teries were alone complete. Phellia browni and capitata are characterised by 

 the unusual strength of the sphincter and its peculiar contraction into two 

 parts, which does not occur in other species. The size and prominence of the 

 acontia are also striking features. Both species have only 3 cycles of mesen- 

 teries. 



Walton (*) finds that specimens of Actinia equina living in exposed situations 

 are dark red, while those living under stones or sea-weed are light red or 

 green. The acrorhagi of the sheltered examples are few, small and of a 

 pale blue colour, while in the dark red specimens they are more numerous, 

 larger, of a much deeper blue and often irregular (bilobed, etc.) in form. The 

 acrorhagi are probably defensive (possibly offensive), as they contain many 

 nematocysts, and their colour may be interpreted as warning*. When the 

 anemone is startled, the tentacles are withdrawn and the acrorhagi then become 

 plainly visible. The colour of Sagartia miniata is usually also of a warning 

 nature, but in one specimen it harmonised very closely with its surroundings. 

 The resemblance of Cereus pedunculatus (S. bellis) to its surroundings is pro- 

 bably of protective value, but is also aggressive, for small Crustacea mistake 

 specimens of this anemone for alga3. Gephyra dohrnii is a true instance of 

 protective resemblance. There are also notes on the colours of S. undata, 

 Tealia coriacea and Ammonia sulcata. There is considerable difference in the 

 freedom with which Sagartids emit their acontia. Specimens which have been 

 exposed to constant friction (e. g., the beating of the surf, causing abrasion by 

 shingle, etc.) emit them only after considerable irritation, whereas individuals 

 living in quiet surroundings put them forth freely at the slightest touch. 



Walton ( 2 ) describes the habitats and colours of Sagartia ornata, Bunodes 

 thallia and Hoplangia durotrix, and adds notes on other anemones from South 

 Devon. 



Thieren states that mucous glands are present all over the column of 

 Heliactis bellis, but are in greatest abundance in the sub-tentacular region, which 

 is encrusted with shells. When the animal retracts, the crown of tentacles is 

 withdrawn, and the mass of shells lies on the top of the anemone, which 

 therefore closely resembles its surroundings. Examples of this anemone living 

 in the shore-pools begin to expand only in the twilight; the expansion is appa- 

 rently independent of the tides. 



Pieron regards the closure of Actinia equina, brought about by the decrease 



