112 PLANARTA. 
utility to shew other naturalists the fallacies to which they may be ex- 
posed. 
In as far as I can judge, this Planaria is not to be identified with 
the Planaria torva, as described and represented by authors. 
Of above 100 specimens, collected from what is called the Dropping 
Well at Foulden, in Berwickshire, the largest exceeded seven lines in 
length, by a line in breadth. They were of various colours. Some al- 
most white, cream-yellow, brownish-yellow, blackish, grey, and other 
hues, not excepting greenish. Many seemed sparsely speckled with 
whitish tubercles. In all the back was the darker surface. 
These creatures feed readily on animal substances, also on the muci- 
laginous softer parts of decaying vegetables. In a state of repletion, 
the distribution of the interanea, somewhat lower than the second ven- 
tral pore, becomes visible. The aperture for protrusion of the proboscis, 
is a little higher. The margin of the body, both here and in several 
other species, remains always transparent, thus denoting extraordinary 
delicacy of the vessels if any pervade it. 
Among the favourite substances most accessible, is the snow-white 
pupa, dwelling in the same place with the Planariw. Of this they are so 
greedy, as actually to devour it alive. If divested of the covermg wherein 
it reposes awaiting its metamorphosis, the creature is beset on all sides 
by a ravenous multitude of these diminutive enemies. In vain it wrestles 
and struggles to be free of such contemptible assailants, those which 
apparently are incapable of protecting themselves. But the proboscis 
of the Planaria, now a formidable weapon, sheathed in the vulnerable 
parts of the abdomen, absorbs the softer matter, and the predacious host 
retreat elutted with the contents, leaving only an empty skin behind, with 
the thorax and limbs entire. 
The colour, size, and whole aspect of the animal, are materially 
affected by the quantity and the quality of the food. One of large dimen- 
sions, from dingy white, became slate-grey in ten days. The specimens, 
Plate XVL., figs. 10, 11, were blackish-grey and brown. The position of 
two eyes is very distinct in the head, enlarged, fig. 12, and they become 
still more conspicuous when compressed between two glass plates, as 
practised by some naturalists, fig. 13. 
