54 
THE \rOYAGE OF H.M.S. CHALLENGEE. 
in Palmyra it assumes tlie form of a transverse collar or scale, forming a double row. 
The entire bristle is curved on itself, and it is difficult to see one on the flat. They are 
by no means brittle, but on the contrary resist a considerable strain without fracture. 
Immediately beneath the foregoing great bristles are a series of fine, elongated hair-like 
bristles, with an extremely attenuate tip, which is marked with minute roughnesses or 
points, so that foreign matters of all kinds adhere. The same series occurs in Pontogenia. 
The ventral bristles (PI. VIa. fig. 9) are stout and somewhat fragile. They rather 
increase in size than diminish from below upward toward the bifid tip, which is termin- 
ated by a simple, slightly bent hook, with a short, strong spur at the base. 
The dorsal cirri occur both on feet provided with scales and on those without them ; 
the former arrangement having been seen in front, the latter in certain of the posterior 
segments ; but the specimen is not in a fit state to show the precise condition in regard 
to the serial arrangement. These have the same shape as the tentacular cirri, only 
they become more slender and elongated posteriorly. The ventral cirrus is short, but it 
has the same distal process (the so-called “articulation”) as the dorsal. A careful con- 
sideration of the appearances presented by the cirri shows that Savigny s original de- 
scription of the organs in Palmyra aurifera would equally suit the foregoing. They are 
“ greles, cylindriques, termines, par un petit filet egalement cylindrique et renfle au 
bout.” The figures and description of Savigny’s form by Audouin and Milne-Ed wards 
bear out this view. Moreover, the whole structure of the organs (as given under the 
tentacular cirri) so closely resembles the same parts in Claparede’s new genus Pontogenia 
thaf it may be doubted whether much reliance can be placed on the so-called quadri- 
articulate tentacle. The latter would be very exceptional in the group, while the inter- 
pretation given above would be in accordance with that characteristic of the family and 
its allies. 
The first pair of scales are borne on the third foot, and the fourth is also elytrophor- 
ous. The succeeding scales seem to be mostly alternate. No trace of a scale occurred on 
the first foot (which is turned forwards) in the specimen. The first scale is smooth, 
shining, and diaphanous ; and beyond a series of parallel streaks and a firm border shows 
nothing noteworthy in structure. Their number would seem to be about fifteen, and 
they cover the back completely. 
In the structure of its body-wall this species is Aphroditacean. It possesses a similar 
proboscis and muscular system, and its dense cuticle on the ventral and lateral regions 
is thickly covered with the pedicled globular papillse. Moreover, the disposition of the 
nerve-cords nearly approaches A-phrodita, though they are ^proportionally larger, and 
the area in which they lie is narrower, the oblique muscles, indeed, touching the cords 
at their insertion. 
Savigny^ in 1820 established the genus Palmyra as one of his Aphroditaceans, 
^ Syst. des Annel., p. 16 . 
