326 MR. E. W. SHANN ON THE 
In the majority of Teleosteans a small muscle is cut off from 
the latero-dorsal portion immediately above the lateral line. 
From the distinctive coloration which it frequently presents it 
has become known as the ‘‘red muscle” or “red fibres.” It is 
not merely differentiated from the latero-dorsal portion by the 
colour of its fibres, or even by their direction, which is parallel 
to the long axis of the body (whereas those of the main muscle 
are directed slightly upwards and backwards); but a distinct 
fascia separates it in each myomere (see text-fig. 3, rf. p. 334). 
A similar “ red muscle” is cut off from the latero-ventral portion 
immediately below the lateral line. The “red muscle” is 
mentioned by Chevrel; we have seen that it was also recognised 
by Maurer. Chevrel states in another part of his text that this 
muscle is constant neither in presence, nor in form, nor in tint, 
nor even in its relations with the lateral nerve. Further, in 
Humphry’s paper (op. cit. p. 294) the following words in reference 
to fishes appear in a footnote :—“..... and the lateral furrows 
are commonly occupied by muscular fibres which bear the trans- 
verse septa, but which are more closely connected with the skin, 
and peel off with it more easily than the rest of the lateral muscle. 
These fibres are more vascular than ordinary muscular fibres ; 
and in a piece which I examined from a Dace they contained 
more oil than the other muscles. Stannius (Handbuch der 
Zootomie (2), 112) says that they, in addition, present micro- 
scopically the appearance of tissue in process of conversion into 
muscle. I did not find that to be the case. With the exception 
of the excess of oil, they represented the usual microscopical 
characters of striped muscle.” Such observations as I have 
made go to support Humphry’s statements. The “red muscle” 
ovadually disappears anteriorly, so that it never reaches the 
shoulder-girdle. 
taraine next to the ventral moiety, we find, in the trunk 
region, an exact repetition of the condition that has been 
described for the dorsal moiety. Following Humphry’s nomen- 
clature, which we have used above, let us designate the area 
immediately below the lateral line, comprising the backwardly 
and downwardly directed arms of the V- shaped myocommata, as 
the latero-ventral portion, and the area between this and the 
mid-ventral line (or the infracarinales muscles, where such are 
present) as the mesio-ventral portion (see text- fig. 2, Z.V. and 
MV.). It will be apparent, on turing back to ‘the tabulated 
summary of the views of the various authors, that this division 
of the ventral moiety of the lateral muscle meets with more 
general recognition than does a corresponding division of the 
dorsal moiety. Tracing these portions forward to the shoulder- 
girdle, we find that thet apices of the backwardly and downwardly 
directed V- shaped myocommata rapidly approach the lateral line: 
in other words, the latero-ventral portion rapidly disappears. 
MeMurrich states that this portion (his “3rd portion”) dis- 
appears in Amiurews before reaching the shoulder-girdle; such is 
