472 
WORMS. 
(B. kewense) having been first obtained in the plant bouses at Kew. It is a 
striking creature, measuring upwards of a foot in length when fully extended, and 
structure of a dendroccelian (enlarged 5 times). 
•11 
having the grey colour of its skin relieved by three dark longitudinal bands running 
along the hack from the head to the tail. It is exceedingly flexible and contractile, 
looking sometimes short and stout, and at other times long 
, c :? and narrow. The head is susceptible of many changes of 
form, assuming the shape of a hammer-head or the blade 
of a cheese-cutter, and the next moment being tongue¬ 
shaped. The skin is richly supplied with glands, secreting 
a sticky slime, by means of which the Bipalium is able to 
ascend perpendicular surfaces, and to lower itself from a 
high point by letting out a thread of the material. It is said 
to feed upon earth-worms, and to propagate by division; the 
tail-end breaking off and growing into a second individual 
by acquiring a head, proboscis, and intestine. Land 
planarians are abundant in the damp tropical forests of 
Ceylon, South America, and Australia; and a rich population 
of allied forms frequents the sea. One of the most striking 
of these marine forms is the tufted planarian ( Thy.sanozoiim ), 
represented in the illustration on p. 473. Here the back is 
covered with many rows of dark-coloured tufts; the lower surface being pure 
white, and the head end furnished with a pair of ear-shaped lappets, in which the 
sense of touch appears to be concentrated. The creature is shown clinging to a 
SMOOTH POLYCELIS. 
ci, The animal; c, The eyes. 
(enlarged twice). planarian worm, Planaria gonocephala (enlarged). 
branch of seaweed, with the head elevated so as to exhibit its lower surface, and 
feeling for a new surface of support. Planaria gonocephala, figured above, is one 
of the land forms. The general structure of the intestine in all the animals of this 
group is shown in the illustration at the top of the page. 
