TRANSACTIONS OF SECTION I. Sll 



Trinchese, ThanliofTer, aud Vollimann ; as pathological structures by Fraiikel, Eiseu- 

 lohr, Millbacher, Eichhorst, Babinsid, and Meyer ; as physiological structures, 

 without however assigninj^ any special function to them, by Mays, Koth, Blocq 

 and Marinesco, Pilliet, Christomanson and Strossner ; and finally, as sensorial 

 nerve-endings, by Kerschner, lluffini, Sherrington, and Sihler : Sherrington having 

 shown conclusively by the degeneration-method that the spindle-nerves are spinal 

 root-ganglion nerves. 



VVe were concerned more particularly with the ending of the spindle-nerves in 

 the muscle-spindles ; our observations were as follows : — 



In the frog the spindle-nerves terminate in fine, varicose fibrils, which run 

 along, outside of the sarcolemma, on the intrafusal fibres. 



In the snake only one intrafusal muscle-fibre is found in the muscle-spindles. 

 The spindle-nerve enters the spindle from the pole, and breaks up into several 

 nonmedullated branches, which follow along by the side of the intrafusal fibres, 

 giving ofi" in their course flat, band-like off-shoots, which partly or completelj-^ 

 encircle the intrafusal fibre. 



In the tortoise the spindle-nerves end in nonmedullated branches, which flatten 

 out into irregular, notched endings having a serpentine course ou the intrafusal 

 fibres. 



In the bird the spindle-nerves terminate in nonmedullated fibres, which have 

 the appearance of a repeatedly folded ribbon. 



In mammalia the spindle-nerves terminate in ribbon-like endings, which are 

 often distinctly wound around the intrafusal fibre (dog, cat and rat) iu the form of 

 a spiral — annulo-spiral endings ; or may branch and have a zigzag course on the 

 intrafusal fibre, in which case few spirals are seen (rabbit and probably also man). 

 The ribbon-like nonmedullated fibres terminate by branching and ending in disc- 

 like expansion — flower-like endings of Ruffini. 



Some few observations are at hand which go to show that the intrafusal fibres 

 have a motorial ending. In this respect we corroborate Kerschner. 



We have regarded the muscle-spindles as sensorial end-organs. 



3. The Mtiscle-spindles in Pathological Conditions. By O. F. F. Grunbaum. 



4. The Ear and the Lateral Line in Fishes.^ By Frederic S. Lee, Ph.D. 



The chief morphological facts upon which the tbeoiy of the origin of the ear 

 from the system of the lateral line is based are similarity in structure of the adult 

 organs, in innervation, and in ontogeny. Physiology seems able to present at least 

 circumstantial evidence in favour of this theory. The author has investigated the 

 functions of the ear and the sense-organs of the lateral line in fishes. 



1. The Ear. — The results may be tabulated as follows : — 



Functions of the Ear Sense-organs 



I. Dynamical functions in ^ 1. Rotary movements. Cristse acusticje. 



recognition of . . J 2. Progressive movements. Macute acusticae. 



II. Statical functions in 1 „ t. •^- • -mt ^ ,.• 



recognition of f -Position m space. Maculae acusticas. 



Tlie above functions are divisions of the general function of equilibration : the 

 sense-organs of the ear deal with the equilibrium of the body imder all circum- 

 stances, both in movement and at rest. 



In vertebrates above the fishes we must add to the above : 



III. Auditory functions in "j 4. Vibratory motions. Papilla acustica basi- 

 recognition of . . / laris. 



Experiments by the author and by Kreidl prove that fishes do not possess the 

 power of audition. Hence the ear in fishes is purely equilibrative in function. 



' Published in the Am. Journ. of Physiology, Jan. 1898. 



