A COMPARATIVE STUDY OF STRIATED MUSCLE. 35 
of the “‘ gizzard,” are forms which exhibit the striated character 
of the muscle in an exceptionally strongly marked form, since 
the striations in European species have been overlooked by 
various observers (e.g. Hisig') who had given the subject 
their attention previously, and have not been recognised by 
others (e.g. St. Joseph?) who have looked for them since. In 
fact, though I have not found any Australian member of the 
genus Syllis in which these striations are not distinguish- 
able, there are some in which they are very few in number and 
not strongly marked, so that but for the knowledge derived 
from a study of the species named above one might very 
readily overlook them; and in the genus Gnathosyllis of 
the same family the muscle is entirely unstriated. 
Emery? has more recently described striated fibres of a pecu- 
liar type occurring in another Polychet, viz. Nephthys 
scolopendroides, and forming a complex system of narrow 
bands. These are broad fibres, more or less cylindrical in 
cross section, and enclosed in a delicate sarcolemma with scat- 
tered nuclei, but have, according to Emery, neither nuclei in 
their interior nor axial granular substance, nor any other pro- 
toplasmic residuum. Their contractile substance is very 
readily broken up into slender fibrils, which show a typical 
striation with alternating, less highly refracting and less 
readily coloured, and more highly refracting and more readily 
stained, transverse zones. The striations are not straight, but 
pursue a zigzag course across the fibre. Each muscular band 
or cord Emery describes as being developed from a single 
flattened cell which produces on one of its faces a lamina of 
striated muscle-substance. 
I have only had at my command a preserved specimen of 
Nephthys scolopendroides which is not in a favorable 
1 * Ueber das Vorkommen eines Schwimmbiasenahnlichen Organ bei Anne- 
liden,”’ ‘ Mittheil. aus der Zoologischen Station zu Neapel,’ ii Band. 
2 « Tes annélides polychetes des cotes de Dinard,” ‘ Ann. des Sci. Nat.,’ - 
Zool., vii® série, tome 1 (1887). 
3 «Tntorno a la moscolatura liscia e striata della Nephthys scolopendroides,” 
‘ Mittheil, aus der Zool. Station zu Neapel,’ vii Bd. (1887). 
