26 



detached from the polypites and move through the water in grace- 

 full pulsations. A more complete contrast to the stationary 

 Zoophyte in form and in habit cannot be imagined, than these 

 medusiform zorids thus sent forth laden with the seed of new 

 commonwealths. 



Frail and delicate as most of these Zoophytes appear to be, 

 yet have the considerable advantage over some other and larger 

 animals. For their tentacles and some other parts are armed with 

 a large number of specialized cells from which threads carrying 

 a poisonous fluid are emitted, so as to wound and paralyze 

 creatures which otherwise would avoid capture. 



Scattered on the sands, especially after a gale, will be seen 

 strange-looking, tough, gelatinous masses of yellowish colour, 

 which fishermen call " pipe weed," although they are really 

 colonies of Alcyonidium gelatinosum — one of the Polyzoa, and 

 therefore much higher in the scale of being than any of the 

 Hydrozoa. 



A colony, founded by a single individual, increases by 

 budding, and at first forms a more or less cylindrical extension 

 from the point of attachment. Then short lobate processes 

 appear, and sometimes longer straggling branches. 



An old writer says of Alcyonidium, then known by the name 

 of " Sea Ragged Staff" : — " It is of a dark yellowish colour, and 

 buncheth forth on everie side with many unequal tuberorities or 

 knots." It only appears uncouth when out of its proper element. 

 Put a piece into an aquarium and it will soon be covered by a 

 delicate hairy film due to the protrusion of the tentacular wreaths of 

 thousands of polypites which are closely packed together in the 

 common dermal system, and under these conditions it presents a 

 very different appearance. When viewed with a hand lens or a 

 microscope, many interesting details are discovered. The poly- 

 pides are highly sensitive, and instantly withdraw their tentacles 

 when alarmed. Attention is drawn to Alcyonidium because it 

 differs in general aspect from the majority of the Polyzoa, and 

 because, at certain times, it is a very common object of the 

 sea shore. 



When strolling on any shingly beach, shells and pebbles 

 may often be found pitted with numerous perforations. When 

 these are seen to be roughly arranged in p<iirSj there is no doubt 

 that they have been made by a curious little worm about ^in. 

 long when full-grown, known as Spio Seticariiis. 



Wherever these indications are seen the living animals are 

 not far off. They can generally be found on shells or other hard 



