IN THE INVERTEBRATA. 53 



in the new Theco-medusa of Professor Allman, and in Campanu- 

 laria each individual retiring into its horny dwelling when 

 danger threatens a phenomenon that involves a sense of 

 danger, a knowledge of the means of avoiding or escaping 

 it, and the adoption of these suitable means in prompt 

 action. What is essentially the same process, however, has 

 already been described in Vorticella among the Protozoa 

 (Infusoria}. In the pursuit and capture of prey various of 

 the Ccelenterata ' excel in dexterity,' Dr. Macintosh, of British 

 annelid celebrity, writes to me. Dr. Andrew Wilson speaks 

 of the ' intelligent seizure of matter or pabulum adapted to 

 its growth ' by the Hydra. 



In the third subkingdom the Annuloida and of its class 

 the Echinodermata we are told that brittle stars 'can scarcely 

 be procured for a museum in a tolerably perfect state, be- 

 cause they throw off ray after ray, and in fact break them- 

 selves to pieces, upon any alarm ' (' Chambers's Encyclo- 

 paedia '). The 'Guide to the Brighton Aquarium' also speaks 

 of this habit of starfishes, ' when irritated, of dismembering 

 their bodies by throwing off their arms. The spiny star 

 .... has shown a tendency to so mutilate itself ; and this 

 practice extends to every specimen yet introduced into the 

 Aquarium.' Houzeau, too, points out the effect of emotion 

 on Ophiocoma in causing it to fall to pieces. 



In the fourth subkingdom the Annulosa a considerably 

 greater range or variety of mental phenomena is met with. 

 Among the Annelida, the Tubicolse, or tube worms, retreat 

 into their abodes ' at the slightest alarm ; ' a phenomenon, as 

 we have seen, that occurs even among the Protozoa. There is 

 selection of materials of construction, as well as constructive 

 art, in Terebella (Carpenter) phenomena, however, that are 

 to be found so low down in the zoological scale as Amoeba. 



It is well known that the angler desiring bait has only 

 to create slight succussion of the soil, by stamping on it, to 

 lead his prey, the earthworm, to come to the surface, a cir- 

 cumstance usually attributed to the dread of its enemy the 

 mole, which makes a somewhat similar movement of the 

 earth in its mining operations. If the fact be as stated, and 

 its explanation be accepted, we must have here a distinct 



