14 Dr. & the Rev. S. Graham Brade-Birks— 
this animal was luminous on stimulation later. The same 
gentleman has since sent us an example from another 
Lancashire locality captured on the 9th of August, 1919, in 
the parish of Northtown, about two miles from Padilam and 
four from Burnley. 
We have not been successful in seeing luminescence in 
Lancashire or Norfolk under natural conditions. 
Apparatus. 
With living material almost at the very door of our own 
laboratory in Darwen, a problem of first importance was the 
inveition of apparatus for the examination of these animals 
alive under the microscope. Eventually we hit upon the 
plan of hinging together two sheets of glass each 1:5 mm. 
thick, some 81 mm. broad, and some 107 mm. long 
(=31" x 44" =photographic quarter-plate), by means of a 
stout piece of adhesive tape (Pl. I. fig. 7). Such a glass-holder 
will rest splendidly upon any ordinary microscope-stage. 
To secure a vigorous adult specimen of G. carpophagus in 
the holder it is only necessary to open the apparatus to its 
full extent and allow the animal to walk on one of the 
sheets and to close the other down upon it gently. The 
glass is sufficiently heavy to hold such a specimen without 
injuring it at all. Smaller specimens need a holder of 
smaller dimensions, and with larger species heavier glass 
could be used with advantage. If one wishes to examine 
the ventral surface of an animal in the holder, since this 
apparatus is symmetrical above and below, it is easy to turn 
it upside down and examine under diieut light applied by 
means of a bull’s-eye condenser (Pl. I. fig. 8). For experi- 
ments concerning the secretions of the elands the same holder 
ean be used apart from the microscope, but some form of 
artificial stimulation is nécessary. We have generally found 
that the current from an induction-coil is the best available. 
To apply this stimulation electrodes are needed inside the 
holder in contact with the animal’s body, and for this 
purpose we have found two strips of tin-foil, a centimetre or 
more in width and about 10 centimetres ‘long, very con- 
venient. 'T'o apply the electrodes the animal is placed on 
one side of the open holder, as previously described, and the 
two electrodes are laid upon its back so that their ends will 
abs beyond the closed edges of the sheets of the 
holder*, the upper sheet of the holder is then gently 
* As a matter of fact, the electrodes can be attached to the upper 
plate of the holder, some time previously, by means of an adhesive, but 
