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Transactions of the Society. 
somewhat shrivelled, and very little in it. Another specimen had 
only three of the sacs restored ; one of the posterior pair still 
collapsed. 
We were not able to repeat this experiment, at the time of 
completing these notes, owing to lack of supplies of larvae. 
The extraordinary vitality of this creature has frequently been 
commented on, and we will bring our remarks to a close by refer- 
ring tb the behaviour of a Gorethra which was crushed in a live 
box. We were observing it under dark -ground illumination, the 
muscles appearing clear and translucent. At the moment of 
death a change took place, and they became semi-opaque and 
iridescent, the alteration taking place quickly through the whole 
muscular structure. Peristalsis commenced, indicated by a bulbous 
expansion at one end of a muscle, which ring-like swelling 
travelled its entire length, expiring at the end, this action repeat- 
ing itself on the same muscle in the reverse direction. Occasionally 
two impulses commenced, one on each end of the same muscle. 
The ‘"expansions” slowly approached; when in contact they 
merged, and the swelling subsided. 
These movements, together with the pulsation of the dorsal 
vessel, had not ceased after a period of eleven hours. 
Summary. 
1. The variety of hairs, including those on the three pairs of 
sensory organs, or vestigial legs, on the thorax, are of greater 
importance as a means of detecting and locating moving objects 
than the large compound eyes. 
2. The vestigial legs and ten pairs of vestigial spiracles supply 
confirming evidence, if that were necessary, that this larva was at 
one time a terrestrial form. The double row of minute, and two 
large, hooks tucked away in a pocket on the ventral side of the 
anal segment is an obsolete retractile hooked foot, used during its 
terrestrial existence. 
3. Owing to the nature and construction of the four air sacs 
they are non-compressible. 
4. Respiration takes place during the up-and-down movement 
of the larva, these movements bringing about a diminution or 
increase of pressure inside the sacs, causing a flowing in or out of 
the gas. 
5. There is very strong evidence of the integument being 
impervious to air or water ; the necessary gas for respiration is 
probably secreted by the cells contained in the tubes aiising from 
the valve ends of the four air sacs. 
6. Miall suggests that the pigment spots may assist in the 
act of respiration. It is significant that these spots are crowded 
