212 Proceedings of the Royal Society 
minutely marked by fine transverse lines, as in tbe massive muscular 
proboscis of Lepidonotus and Aphrodita. These circular striae are 
much finer in front, and gradually widen towards the posterior part 
of the coloured or anterior region, which in almost all the 
specimens is firmly contracted — from the peculiar structure of the 
body-wall. The dorsal is distinguished from the ventral surface by 
a longitudinal furrow (on each side of the median line), which cuts 
off a ridge or segment overlying the rectum. In many, the body 
gradually dilates toward the end of the anterior region, and 
an enlarged pale “bladdery” part often occurs — marked by a 
close series of longitudinal bands — crossed externally by fine 
transverse striae, so that the region has a tesselated appearance. 
Such an aspect, of course, diverges very much from the eight 
longitudinal bands in Edioardsici and Cerianthus, though, as will 
afterwards be noticed, there is a certain structural resemblance 
between the muscles of the diverse groups. Even in the somewhat 
narrower region of the Phoronis, behind the latter part, traces of 
these longitudinal bands (the muscular fasciculi) are visible. 
Einally, the body ends in a more or less clavate or bulbous region, 
which is generally devoid of such markings. 
The contracted anterior region of the body, after the muscles are 
fully formed, presents externally in transverse sections the chitinous 
cuticula, then the hypoderm, which even in fine sections is almost 
opaque from the deposit of blackish pigment. Beneath is a 
translucent and probably elastic basement-tissue of considerable 
thickness. The circular muscular coat, which immediately follows, 
is not much developed at the commencement of the region, the 
radiating series of fibres which pass from the body -wall between 
the pennate portions of the next coat and the oesophagus, 
apparently performing the chief functions necessary. The next or 
longitudinal coat is regularly arranged in bands, which in transverse 
section present a most regularly pennate appearance — a pair of 
dense fasciculi, with a somewhat fan-shaped series of striae, occurring 
at the base (externally), within which the arborescent or complexly 
pennate fibres project. It is interesting to notice a kind of gradation 
between the lax pennate arrangement of the longitudinal muscular 
bands in Peachia , the coarse pennate system in Phoronis , and the 
more finished pennate plan of the muscles in the Eriographididae. 
