658 VARIOUS BREEDS OF SHEEP IN GREAT BRITAIN. 
outline is broken and interrupted ; and presently an irregular 
cluster of granules is all that remains, and these soon 
disappear. 
It sometimes happens that the nuclei perish while in con- 
tact, before the fibre elongates ; but the subsequent changes 
are the same. 
The striae generally first become visible at this period, 
immediately within the margin of the fibre. 
The fibre is subsequently increased in size, and its deve- 
lopment is continued by means of the surrounding cytoblasts. 
These attach themselves to its exterior, and then become 
invested by a layer of the surrounding blastema. Thus, as 
it were, nodes are formed at intervals on the surface of the 
fibre. These invested nuclei are at first readily detached, but 
they soon become intimately connected and indefinitely 
blended with the exterior of the fibre. All its characters are 
soon acquired ; the nuclei at the same time gradually sink 
into its substance, and an ill-defined elevation, which soon 
disappears, is all that remains. 
Lastly, the substance of the fibre becomes contracted and 
condensed. The diameter of a fibre towards, or at the close 
of intra-uterine life, is considerably less than at a much 
earlier period. 
At the period of birth muscular fibres vary much in size. 
The several stages in the development of muscular fibre, 
above mentioned, do not succeed each other as a simple con- 
secutive series ; on the contrary, two or more are generally 
progressing at the same time. Nor does each commence at 
the same period in all cases . — 'Microscopical Journal . 
ON THE VARIOUS BREEDS OE SHEEP IN GREAT BRITAIN, 
ESPECIALLY WITH REFERENCE TO THE CHARACTER 
AND VALUE OF THEIR WOOL. 
By John Wilson, Professor of Agriculture in the 
University of Edinburgh. 
( Continued from p. 5 88.) 
llomney Marsh . — The breed of sheep met with in the Rom- 
ney Marshes has long been recorded as peculiar to the 
district, occupying the same locality, and still to a great 
extent preserving its own particular characteristics amidst 
the many changes and improvements that have so materially 
