ON THE PHYLOGENY AND MORPHOLOGICAL POSI- 
DIONIOE THE TERMINAL BUDS OF FISHES:* 
By C. Jupson Herrick. 
These curious sense organs occurring in the skin of certain 
fishes have been a source of perplexity and controversy among 
morphologists since their discovery by Leypic in 1851. They 
are found freely scattered over the surface of the skin of the 
head and trunk in certain teleostean and ganoidean fishes, par- 
ticularly in exposed situations, and hence by many observers 
have been regarded as tactile organs. Indeed, MERKEL in 
1880, having failed altogether to find the proper tactile nerves 
in the skin of fishes belonging to what we now designate as the 
general cutaneous system, supposed that these organs, together 
with the neuromasts or organs of the lateral line system, were 
developed in compensation for the absence of the typical free 
tactile nerve endings of the other vertebrates. This we now 
know to be wide of the mark, for all fishes which possess either or 
both of the systems of special sense organs mentioned above 
also possess in the same cutaneous areas an abundant general 
cutaneous nerve supply for tactile sensation. 
We must distinguish at the outset three distinct types of 
sensory nerve endings in the skin of fishes and then inquire in- 
to their respective morphological rank; viz., (1) the general 
cutaneous nerve termini, (2) the neuromasts, or organs of the 
acustico-lateralis system of sense organs, (3) the terminal buds, 
or end-buds. 
(1) The first type comprises the ordinary tactile nerves, 
making up the greater part of the spinal dorsal roots, but rep- 
resented in certain ones only of the cranial nerves. They are 
1 Studies from the Neurological Laboratory of Denison University, No. 
XVII. 
