7. Anthozoa (incl. Hydrocorallia). A. Zoantharia. 27 



of the base Actinoloba dianthus may move 7 inches per day and Actinia and 

 Anthea even further. Some of the more active species, e. g. Anthea cereus, 

 may progress on the tips of their tentacles. Particulars are given of the 

 appearance of anemones in localities where, a short time previously, careful 

 search had failed to establish their presence. Anemones eat almost any prey 

 which comes among their tentacles but molluscs seem to be able to avoid 

 capture, possibly on account of the abundant mucus on their skin. Eolis pa- 

 pillosa is a formidable enemy of anemones, killing many but avoiding Tealia. 



Hargitt( 1 ) records observations on Eloactis producta, an anemone which burrows 

 in sand and is nocturnal in habit, for during the day only the tentacles pro- 

 trude from the burrow but at night half the body also is visible. In the 

 laboratory, specimens expand only in light of low intensity, this action is not 

 due to any periodic response, for on covering and so darkening the aquarium 

 the anemones began to slowly protrude and in half an hour the body was ex- 

 tended an inch beyond the surface, on exposure to light they immediately 

 began to retract. By directing a narrow beam of light on various parts of the 

 animal it was found that the oral region, including about one third of the body, 

 was more sensitive than any other part, the aboral portion yielded no response, 

 and the tentacles were less responsive than the adjacent part of the body. In 

 a general way these results confirm the Hertwigs' description of the distribution 

 of sense cells in Actiniae. Sagartia modesta, which is also a burrower in 

 sand and nocturnal in habit, responded with less promptitude and clearness than 

 E. but on illuminating the tentacles, which are very numerous, there was 

 immediate reaction. S. leucolena prefers the underside of rocks and other 

 sheltered situations, S. lucicp and Metridium marginatum are oftener found in 

 more open situations. Of these S. leucol. is more responsive to light stimuli 

 almost always attempting to escape from direct rays or, if this be impossible, 

 it entirely closes assuming a hemispherical shape, the degree of contraction and 

 of light intensity being closely correlated. S. Incite and M. m. are indifferent 

 to light. E. rejects pieces of crab, fish, clam, etc., but readily takes living 

 Balanoglossus or Hydroides. Irritation during the act of swallowing determines 

 an anti-peristalsis of the stomodseum and the food is rejected. Specimens of 

 E. behave differently in regard to burrowing, some burrow quickly but others 

 lie on the sand for a considerable time before attempting to do so. The author 

 believes that several species have sensory perception of photic stimuli as well 

 developed as in the earthworm and clam and that the action of light is an 

 important factor in influencing the behaviour of several species, for example, 

 in their burrowing habits, for neither geotropism nor stereotropism afford as 

 applicable explanations of the various conditions described. See also Hargitt( 2 ). 



Bohnf 1 ) finds that specimens of Actinia equina var. rubra are less inert the 

 more light they have received during the preceding weeks, they not only more 

 readily expand but remain expanded for a longer period. A periodicity cor- 

 responding to day and night seems to be established. Past influences remain 

 manifest although more recent changes have been introduced in the conditions 

 to which the animals are subjected. The author concludes that when specimens 

 of e. are illuminated, during several days, in different ways the living sub- 

 stance is variously affected and different physiological states are produced. - 

 Bohn( 2 ) states that after repeated shocks, either by means of a current of 

 water or by shaking, specimens of e., after a short period of expansion, close. 

 Specimens are enfeebled by prolonged action of the water current and contract 

 like those enfeebled by a long sojourn in the dark or in excessive insolation. 

 The tendency to total retraction of the tentacles is an index of a state of 



