28 W. BLAXLAND BENHAM. 
renewed investigation with other preservatives and stains may 
lead to a different interpretation of this “tube ;” but, so far 
as my preparations go, | cannot think that this is an “inner 
neurilemma,” or that the contents form the “ punktsubstanz.” 
The muscles of the body-wall are chiefly interesting for the 
great thickness of the longitudinal coat, and the very feeble 
development of the circular coat in the greater part of the 
body, though anteriorly this coat becomes rather thicker. 
The ‘inner coat of circular muscles,” which has so often 
been described for the Paleonemertini, has been identified 
by Birger as the muscle of the rhynchocele (proboscis sac) 
and gut, which, owing to the slight development of the paren- 
chyma, comes to lie immediately within the Jongitudinal coat. 
This explanation brings the muscular system of the Palzone- 
mertini into agreement with the general scheme of Nemertine 
musculature. 
This inner coat (r/.c.) is in the present worm very thin indeed, 
but can easily be recognised in longitudinal sections. I have 
exaggerated its thickness in the figure of a transverse section, 
This inner coat can be traced as a sheath round the rhynchoceele 
and intestine (éné. c.), and a second coat surrounding the rhyn- 
choceele alone. 
Birger describes a decussation of this inner coat in the 
median dorsal line. I am unable to satisfy myself whether 
this exists in the present worm; but traversing the longi- 
tudinal muscles is a vertical strand of tissue (fig. 10, a.) stain- 
ing like the basement tissue and continuous with it dorsally, 
and with a similar tissue surrounding the rhynchoceele ; 
whether the circular muscles accompany this strand—as I 
believe they do—I was unable to determine. The intestine, as 
I have just stated, is partially—i.e. on the ventral side— 
surrounded by a layer of circular muscles; in addition, its 
dorsal wall is formed by a fairly thick layer of longitudinal 
fibres (int. lg.), lying between the intestinal epithelium and 
the wall of the rhynchoceele. 
The proboscis presents throughout the greater part of its 
extent a glandular epithelium, surrounded by circular muscles, 
