THE STARFISHES OF THE HAWAIIAN ISLANDS. 
1097 
The whole abactinal and lateral surfaces cf body are paved with very thin, delicate, papery plates, 
of a peculiar subcruciform or 4-lobed contour, They are immersed in thin, tough integument, and 
imbricate strongly, especially on sides of body, where they are arranged in fairly regular transverse 
rows. Individual plates are difficult to distinguish until the integument is dry. Each plate bears a 
sheathed tuft of spicules. Papulse single. 
Adambulacral plates are of curious shape, set somewhat obliquely, so that the outer aboral process 
of each plate fits against the outer side of the succeeding plate. Armature consists of an oblique trans- 
verse series of long, slender spinules divided between 2 adjacent plates. That portion of the comb 
nearest furrow is set on an oblique low ridge of one plate, and consists of 7 spinelets, while the outer 
part of series stands on the aboral extension of the adjacent adoral plate and consists of 3 spinelets, 
the entire 10 being united to their tips by a continuous web. The outermost spinelet of consecutive 
series is further united by a longitudinal ventro-lateral membrane which is perforated between each 
adambulacral series of spines. 
Mouth plates are prominent actinally, of the Myxaster type, with a prominent beak aborally, and 
a marginal armature united by membrane. 
Madrepor’ic body large, not multiple. 
This genus differs from Myxaster in the following important particulars: In the peculiar arrange- 
ment of the adambulacral plates and their spines, each transverse series of the latter, although united 
by membrane as in Myxaster , being common to 2 adjacent plates; by the presence of a sort of. aetino- 
lateral membrane uniting the successive adambulacral series, this membrane being perforated ; abactinal 
and lateral plates are thinner and more delicate than in Myxaster , are immersed in membrane, and are 
not so regular along medio-radial region. 
Asthenactis papyraceus, new species. 
PI. XL, figs. 3, 3a. 
Rays 7. R=105 mm.; r=15 mm. R=7 r. Breadth of ray at base about 10-12 mm. 
Rays long, and slender throughout, very flexible, tapering from a fairly narrow base to an attenuate 
extremity. They are subcylindrical, depressed near base. Margin of ambulacral furrow rounded. 
Disk fairly large and ambulacral furrows fairly wide. Ambulacral feet in 2 series, with prominent 
sucking disks. Integument like parchment, rather thin and papery, with numerous imbricating 
subcruciform plates. 
Abactinal and lateral walls of body paved with very thin, delicate, papery plates of fair size, the 
4 processes of each plate having rounded ends. Those at the sides of body are arranged in fairly 
regular transverse rows, and are rather closely imbricated. Here one can count about 4 or 5 plates to 
each transverse row. They imbricate in such a way that the upper edge of a plate overlies the lower 
edge of that just above. Their form and arrangement are perhaps best shown by the figure (pi. xl, fig. 
3). Over abactinal area the plates may be described as stellate with 4 obtuse, often irregular lobes. 
•They are not nearly so crowded as in the lateral walls, and do not appear to be regularly arranged, 
although they still imbricate by their lobes. Between these plates single small papulae emerge. They 
are very inconspicuous, and are present also between some of the lateral plates. All plates are thin 
and of an embryonic character, and their outlines are difficult to discern. When prepared and examined 
under the microscope, they are seen to consist of an open calcareous meshwork of the most delicate 
description. Each plate bears a tuft or brush of long, delicate spicules, 4 or more to each group, the 
whole united by a delicate sheath. Spines of lateral plates are situated on the middle of upper border 
of plate. Surrounding the conspicuous anal opening, at a slight distance, is a circle of 7 tufts, radially 
situated, and larger than any of the others. The spinelets or spicules are very delicate in all these 
groups. Each has a deep longitudinal sulcus running its whole length, in the bottom of which are 
numerous perforations forming about 2 series. The disk is marked by a faint groove extending from 
each interbrachial angle to the periproct. The whole surface of the body is covered with a thin mem- 
brane which obscures the outlines of the plates. This is continued up over the groups of spines, forming 
the sheath mentioned above. 
Ambulacral plates form a rounded margin to furrow, and are of unusual shape. Each is rounded 
on its exposed surface and sends a process aborally, external to the adjacent aboral plate. This pro- 
cess, which is wedged between the succeeding plate and the first row of actinal plates, is really only 
the exposed surface of a more extensive aboral end, overlaid by the adoral end of the succeeding plate. 
Its greatest peculiarity lies in the fact that it bears a group of spinelets which form a continuous series, 
not with the furrow spinelets of their own plate, but with those of the succeeding plate, to which they 
