304 
GEORGE RALPH MINES. 
was then partially filled with water and the long limb of the 
tube placed vertically. The water stood in the tube at a level 
of 2 or 3 cm. above the level of the water surrounding the 
animal. On stimulating the skin there was a marked rise of 
pressure, the water in the tube reaching levels of, e. g. 10, 14, 
and 17*5 cm. in various cases. In many cases Cuvieriau 
organs were extruded; if this happened it was always when 
the pressure approached its maximum. In those instances 
where the pressure reached or exceeded about 17 cm., there 
was partial elongation of the organs extruded. It is probable 
that the operation of introducing the sound so upset the 
nervous system as to interfere with the reflex contraction, 
and thus the pressure reached was insufficient to cause com- 
plete elongation of the Cuvierian organs. It is certain, how- 
ever, that a rise of pressure in the body-cavity precedes aud 
accompanies the discharge of the Cuvierian organs, and that 
even in the injured animal the magnitude of this pressure 
approaches that needed to elongate an excised Cuvierian 
organ. 
The experiments recorded in this uote seem to me to afford 
evidence in support, of Herouard’s view as to the mode of 
discharge of the Cuvierian organs. 
I wish to thank Dr. Cresswell Shearer for his kindness in 
lending me photographic apparatus for this work. 
August, 1911. 
Bibliography. 
1. Minchin. — ‘Annals and Magazine of Nat. Hist.,' 1892, p. 273. 
2. Bartliels. — ‘ Sitz. d. Niederrliein. Gesellscli. f. Natur. u. Heilkund. 
zu Bonn.,’ 1896, p. 76. 
3. Delage et Herouard. — ‘ Traite de Zoologie concrete,’ t. iii, p. 308, 
1903. 
4. Sedgwick. — ‘ Students' Text-hook of Zoology,’ vol. iii, p. 259, 1909. 
