POLYCILETA—BENHAM. 
85 
Genus Scione Malmgren.* 
SCIONE MIRABILIS McIntosh. 
Pista mirabilis McIntosh (1885), p. 454, pi. LI, figs. 1, 2 ; pi. XXVII a, 
fig. 34. 
An unnamed tube, McIntosh (1885), Introduction, p. 10, pi. XLIX, figs. 8, 9. 
Scione spinifera Elders (1908), p. 152, pi. XX, figs. 10-14. 
Scione spinijera Gravier (1911), p. 134, pi. XII, fig. 156 (tube). 
Scione spinifera Elders (1913), p. 561, pi. XLIV, fig. 7 (tube). 
Scione mirabilis Elders (1913), p. 562. 
(Plate 9, figs. 97-100.) 
The material consists of seven individuals, two of which were still within their 
tubes, the rest having been removed therefrom before preservation. 
The tube is nearly straight with the upper free end bent downwards as figured by 
previous authors. One tube measures 150 mm. along the curve, the other attains a 
length of 240 nun.; the lower end is lacking in both, but a greater portion is absent from 
the longer one. The tube has a cylindrical lumen, 5 mm. in diameter ; the external 
surface is raised into four longitudinal ridges which bear the characteristic long spine-like 
processes ; these are from 10-12 mm. in length in the upper region and decrease gradually 
towards the lower end to 1 mm., while in the lowest quarter they are absent. 
In the upper part, for a distance of about 10-20 mm., the ridges die out and the 
spines depart from their regular linear arrangement, becoming scattered over the surface. 
This region is of looser texture than the lower part, there being less mud adhering to the 
basal membrane, and consequently, too, the wall is translucent. 
Embedded in the mud wall are bundles of sponge spicules, such as McIntosh 
describes for Pista ( Scione ) mirabilis ; they are disposed circularly and closely parallel 
to one another. They are present also in the “ spines,” where they are disposed length¬ 
wise. On the surface of the tube wall and on the spines are various colonies of Polyzoa, 
Hydrozoa, and a portion of what seems to be Rhahdopleura, which is unfortunately 
poorly preserved and the polypides are either absent or indistinct. 
The complete worm removed from the smaller of the two tubes has a body length 
of 50 mm. for 92 segments ; its breadth anteriorly is 4 mm. thence tapering to the hinder 
end. Most of the tentacles are lacking, and the few that remain are broken. 
The largest specimen in the collection had already been removed from its tube 
before preservation ; it is about 70 mm. in body length, to which 20 mm. is to be added 
for the length of the tentacles ; its diameter is 7 mm., and the body contains about 90 
segments. This specimen is twisted in the abdominal region and is somewhat soft 
further forwards, so that these dimensions are not absolutely correct. These specimens 
are smaller than the individual of S. spinifera measured by Elders. 
Scione is another re ccupied name, according to Leiper. 
