BILL AND HAIRS OF ORNITHORHYNCHUS PARADOXUS. 151 
nervous character and connections of the filaments. I am in 
entire agreement with this statement: ‘‘ the nervous charac- 
ter” does not exist, and the nervous connections could not by 
any possibility have been seen in the tissues with which I was 
supplied. Although I did not recognise connections which 
could not have been seen, I certainly inferred them, as the 
title of my communication indicates (‘‘ On the Tactile Terminal 
Organs,” &c., ‘Journ. of Physiology,’ 1884). 
The filaments must be regarded as remarkable terminal 
organs, entirely distinct in histological nature from the axis- 
cylinders which terminate in them; and Wilson and Martin’s 
fig. 25 seems to suggest that the change in nature takes place 
at or close to the point at which the medullary sheath dis- 
appears. The appearance presented by the filaments is very 
clearly shown in figs. 3 and 4 accompanying this paper. They 
must be looked upon as a new and interesting form of nerve 
terminal organ, probably epithelial in origin. 
As regards the Pacinian-like bodies, Wilson and Martin 
support my previous account, but they also describe certain 
larger forms of these structures, rather more deeply placed 
than those immediately below the push-rods. Bodies similar 
to those beneath the rods occur in the mouth, and were 
described and figured in some detail in my paper on ‘“ The 
Tongue of Ornithorhynchus” in this Journal (‘ Quart. Journ. 
Mier. Sci.,’ July, 1883, Pl. XXXII, fig. 5). 
The constant occurrence of a group of Pacinian-like bodies 
at the base of each push-rod (figs. 5 and 6) is of great phy- 
siological interest, as it strongly supports the view—widely 
held but as yet unproved—that the function of this form of 
nerve end-organ is to aid the nervous system in the apprecia- 
tion of pressure. The obvious use of the push-rods is, as I 
stated in 1884, “to supply specially moveable areas yielding 
to surface pressure, which is thus communicated to the terminal 
organs below.” 
Another interesting end-organ described by these authors is 
placed among the epidermic cells of the base of the rods. In 
these “lenticular bodies” the axis-cylinder is described as 
