15 
of germinal matter is very much wider than the muscle. 
Often three or four of these masses are seen close together 
(PI. II, fig. 9), while for some distance above and below the 
muscular fibre is destitute of nuclei. The narrowest extre- 
mity of the oval mass is directed in some cases towards the 
terminal extremity of the muscle, in others towards its base. 
There are often three or four fine fibres branching off from 
one stem, and gradually tapering in fine threads towards their 
insertion at the summit of the papilla (figs. 1 & 9). The 
nuclei are three or four times as wide as these fibres. 
The greatest difference is observed in the distance between 
contiguous nuclei connected with the very same fibre. If the 
muscle had gone on growing uniformly iu all parts siuce the 
earliest period of its development, the nuclei would be sepa- 
rated from one another by equal distances, or by distances 
gradually but regularly increasing or diminishing from one 
extremity of the fibre towards the other. 
I think the irregular arrangement of the nuclei in these 
muscular fibres of the tongue is to be accounted for by their 
movements. Perhaps, of a collection of these nuclei close 
together, two may be moving upwards towards the narrow 
extremity of the muscle which is inserted into the connective 
tissue, while the third may be moving in the opposite direc- 
tion. 
Iu some instances a “ fault ” is observed in the production 
of the muscular tissue, as if the nucleus had bridged over a 
space and formed a thin layer or band of muscular tissue, 
which, when fully formed, was separated by a narrow space 
or interval from the rest of the muscle. See PI. Ill, fig. 12. 
In cases in which the nuclei are distributed at intervals 
throughout the muscular tissue, as in the large elementary fibres 
of the muscles of the frog, the formation of the contractile mate- 
rial gradually ceases as the elementary fibre attains its full 
size. A\'hen this point has been reached some of the nuclei 
gradually diminish in size, and their original seat is marked 
by a collection of granules. These granules are sometimes 
absorbed, and the seat of the original nucleus is marked by a 
short line which gradually tapers at the two extremities until 
it is lost. 
It is almost needless to say that no alteration produced by 
the different contractions of the muscle in different parts, 
would account for the position of the nuclei observed in the 
fine fibres of the papillae of the frog’s tongue. 
These views, it need scarcely be said, differ entirely from 
those generally entertained upon the development and forma- 
tion of muscular tissue. They are supported bv detailed 
