NEW ECHIUROID AND SIPUNCULOID WORMS—FISHER 361 
rarely anastomosing. When body is fully inflated the longitudinal 
and circular muscles divide the surface into flat rectangular areas 
separated by rather inconspicuous grooves, but when constriction 
takes place there is apparent a series of more or less convex annuli. 
The middle third of body, except for a ventral zone, about six muscle 
bands in width, is closely covered with slender pointed papilliform 
outgrowths of the cuticle, 1-1.5 mm. long, which give a furry appear- 
ance to the skin. These papillae are continuous with irregularly 
zig-zag subcutaneous canals, above which the cuticle usually forms 
slight welts, which have a direction oblique to the longitudinal axis 
of the dermal rectangles. Each rectangle has its own canal, inde- 
pendent of the others (pl. 12, figs. 4,5). Beyond the papuliferous area 
these canals, or more properly spaces as they are usually branched, 
can be traced forward half the distance to head and also posteriorly 
as they are often self-injected with yellowish material from the coelom. 
On the periphery of the papuliferous area a papilla usually appears 
first at the anterior end of the canal; next at posterior end; then in 
between, until there are four or five to each rectangle. Brown or 
yellow finely divided material, which is sometimes loose in the canals, 
is also found in the bottom of the papillae. If the top of the canal 
is stripped off, a pore at each end is seen to lead deeper into the 
tissue (arrows in pl. 12, fig. 4). If ordinary ink is forced from the 
coelomic side into the pores that exist at intersection of longitudinal 
and transverse muscle bands, it appears in these pores at the ends of 
the subcutaneous canals but is usually blocked by material already 
in the canal. The papillae are highly iridescent in sunlight. The 
area strongly reminds one of the papularium of a sea-star and the 
function is probably the same. 
The terminal knob of the body is very short, broadly rounded 
to subtruncate and the slight margin is capable of disappearing under 
distension. There is a conspicuous terminal pore, and the skin, 
either smooth or longitudinally ridged, is closely beset with micro- 
scopic pores of at least two sizes. 
The short introvert is covered with squamiform’ papillae, which 
increase in size toward the front, near which they decrease over a 
narrow zone to the bare zone behind tentacles. The largest papillae 
are 0.75-1 mm. in length and breadth. é 
The tentacles are composed of very numerous small, grooved, 
foliate elements in subtriangular mats or groups, radiating from the 
mouth, which is ventral to the center. There are seven of these 
from which ridges of tissue converge to the mouth, the odd one 
being the middorsal and much the largest, two are dorsolateral, 
two lateral, and two ventral. On the periphery of the crown the 
space between the major groups is filled in with one to three small 
