204 
ROBERT SCHARFF. 
Halicryptus spinulosus. 
As far as I have been able to ascertain, the spikes on the 
proboscis agree with those of Priapulus. The cuticula, 
however, surrounding the spikes, differs somewhat in not form- 
ing a sheath round them, but a crest of little lancet-shaped 
blades. Figure 1 1 represents a somewhat diagrammatic view of 
their general arrangement. 
At the line of junction between the proboscis and the body 
proper (fig. 11,/.) the spikes become curiously modified. They 
are not always so regularly formed as I have indicated them 
on the diagram, aud generally there are three circular rows of 
them surrounding the proboscis. Occasionally we find some 
that do not exhibit those two prongs at the apex j in fact, there 
may be a number of transitory stages between the ordinary 
form of the proboscis and this peculiarly modified form. 
According to Saenger we find at the apex of the subcuticular 
elevation a large transparent cell containing a quantity of 
yellowish droplets looking like fat. He observed the animal 
in the living state, and noticed that under ordinary circum- 
stances these little prongs are never withdrawn into the 
interior. They form the boundary up to which the invagina- 
tion of the proboscis takes place, and probably act as a kind of 
support. By means of these prongs the worm keeps his 
position even when the anterior part is drawn in, and they 
may also be advantageous in locomotion. I have not been 
able to investigate their histological structure. 
The most interesting of the dermal organs of Halicryptus 
are those of the body proper. They are almost twice as long 
as the ordinary spikes of the proboscis (fig. 3 a, and fig. 11, 
sp. /.). We can distinguish two parts, a lower and an upper. 
The former rests on a broad base tapering somewhat towards 
the apex, while the latter consists of a slender portion resem- 
bling in external appearance the sting of a bee. The hypodermic 
cells filling up the interior of the lower portion are modified 
into three different sets, one being replaced by another as we 
