486 
MR. BOWMAN ON THE MINUTE STRUCTURE AND 
Fish, it is only necessary to procure a fragment (as for instance from the Skate), in 
which the primitive fasciculi arise by tendon. If a minute portion of this tendon be 
now severed with the muscle attached to it and laid upon glass, it may be split up 
without difficulty by means of needles into very minute particles. Some of these may 
be tendon alone, some muscle alone, but others will consist of them both united, and 
will here and there present accidentally a fasciculus distinct from the rest, with its 
little bundle of tendinous fibrils attached. Care must be taken not to confound the 
clear diaphanous sarcolemma, which is almost sure to be made apparent in this 
procedure, and may be wrinkled, with the undulating fibrous tissue. In such speci- 
mens the tendinous and muscular structures are readily distinguishable from one 
another, and the line of demarcation between them is often so definitely in view, that 
no doubt can be entertained as to the genuineness of the appearances. The tendon 
seems to transmit a small detachment of its fibrils to each primitive fasciculus, pro- 
portioned to its size ; which arriving near its extremity, expands towards it, and is 
immediately lost by direct continuity with it (figs. 68. 69.). The fasciculus does not 
commence of a taper form, but is of the same bulk at its extremity, as in any other 
part of its length, and the striae begin from the very extremity of the fasciculus. That 
is, all its fibrillse are of equal length, and terminate on a level. The beads or segments, 
too, are uniform in number on every fibrilla of the same fasciculus, or, in other words, 
the terminal disc is a perfect one. The sarcolemma also continues to invest it to its 
extreme end, and there seems to terminate abruptly. It follows, therefore, that the 
extremity of a fasciculus, if a direct view of it could be obtained, would present the 
same parts as a transverse section, viz. the extremities of fibrillse inclosed by a ring, 
which would be the terminating margin of the sarcolemma. I believe it to be to all 
these parts that the tendinous threads proceed and become fixed, for the following 
reasons : 
1st. Such a fasciculus being regarded lengthwise, an uninterrupted clear line is 
traceable along its edge, and beyond its extremity, where it becomes continuous with 
the margin of the tendinous bundle. 
2nd. The abrupt line of demarcation between the muscle and the tendon is visible 
throughout, as the focus is made to descend through the object, so that as successive 
muscular fibrillse are brought into view with their strise, successive fibrils of the tendon 
also appear. 
In Crustacea and Insects, in which the muscle is united to hard tendinous or ana- 
logous surfaces, the fasciculi terminate unequivocally by a corresponding surface, at 
the margin of which the sarcolemma finds attachment. I have seen this very plainly 
in certain insects, as the legs of the Water Scorpion ( Nepa drier ea). But the class 
of Insects will furnish examples of the clearest kind in direct confirmation of the 
view already taken of this subject in Fishes, and, therefore, showing with how much 
propriety we may probably venture to extend the description there given to the 
higher orders, whose primitive fasciculi have so striking a similitude in every essen- 
tial particular to the same structure in the lower. In fig. 70. are given the ap- 
