170 Mr Mines, Note on the respiratory movements ' 
Note on the respiratory movements of Torpedo ocellata. By 
G. R. Mines, M.A., Fellow of Sidney Sussex College. (From the 
Stazione Zoologica, Naples.) 
[Read 10 February 1913.] 
(Plates III and IV.) 
THE researches of Bethe, Rynberk, Baglioni and others have 
shown that in a great variety of fishes, both bony and cartilaginous, — 
the rhythm of the respiratory movements is very closely dependent 
on peripheral stimuli. It has been remarked that the sequence 
of regular rhythmic movements which are ordinarily called the 
respiratory movements, is liable to be interrupted by movements 
of a different type, in which the cavity of the pharynx is opened 
more widely than usual and then forcibly contracted, driving the 
water out through channels which ordinarily conduct an inflowing 
stream. These movements can be elicited with great ease by the 
introduction of any foreign solid object into the mouth cavity, and 
also by the introduction of bubbles of air: they occur when a fish 
is removed from water, and are called variously gasping move- 
ments, Auspedreflewe or, in the case of elasmobranchs, Spritzrefleae. 
Baglioni* remarks that these spouting movements may be seen 
occasionally if one watches a fish kept in a tank under conditions ~ 
as nearly as possible normal. He attributes their occurrence to 
the entry into the mouth cavity of some foreign particle with the 
inspired water, such as a grain of sand or a shred of mucus: such 
objects are often to be seen in the jet of water shot out by the 
Auspeireflex. Baglioni thus regards the sporadic appearance of 
these movements as being conditioned by the chance occurrence 
of some slight external stimulus. He considers them equivalent 
to a cough or a sneeze. 
While it is undoubtedly true that spouting movements can be 
elicited by very small external stimuli, | have made some observa- 
tions which seem to me to point to a tendency on the part of the 
nerve cells concerned in the reflex to discharge at rhythmic 
intervals which are not correlated with rhythmic external stimuli. 
The development of rhythms of long period in nerve cells is a 
matter of interest from several points of view, and I have therefore 
thought it worth while to give a brief account of these observations, 
which were made incidentally in the course of another enquiry as 
yet unfinished. 
* Z. f. allg. Physiol. vit. p. 177, 1907. 
