THE ECHINODERMS OF THE WOODS HOLE REGION. 
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by the upper-arm plates, and on the side of the notch are 7 or 8 short conical projections or papilla?. 
This series is continuous with another one of 12 small, flat papillae along the genital slit. Just outside 
the disk notch are small papillae on each side of the upper-arm plate. In young specimens all or 
nearly all of these papillae may be wanting. Upper-arm plates rounded distally, more or less pointed 
proximally, separated by the side-arm plates on the distal part of the arm in adults, on the whole 
length of the arm in the young. First under-arm plates oval or triangular with rounded corners; the 
remainder broader than long, the distal edge slightly convex, the proximal with a little point. Side- 
arm plates strongly developed, completely separating the under-arm plates. Tentacle scales small 
and with rounded ends, 7 to 9 for the mouth tentacles, 3 or 4 for each of the first two arm tentacles, and 
1 for each tentacle thereafter. Oral shields somewhat broader than long, pointed within, and broadly 
curved on the outer side; 1.5 mm. wide, more or less. Adoral plates long and narrow, lying along 
the inner sides of oral shields, and meeting within. Oral papillae 3 or 4 on each side of each jaw, one or 
more of them at the point of the jaw; outermost one broadest. Teeth 5 or 6, equal, sharp and flat. 
No tooth papilla'. Interbrachial spaces with small scales, and 1 pair of genital slits. Color in life 
variable, but not bright; generally some shade of gray, more or less variegated with brown, reddish, 
or black; radial shields usually distinctly lighter; arms often banded with gray and greenish. 
Range . — Greenland to Crab Ledge, off Chatham, Mass. ; and possibly m deep water to I'orto Rico. 
(Fish Hawk collection, 1899.) Also from the Arctic Ocean to Denmark. Alaska? Possibly circum- 
polar. Low water to 150 fathoms. 
Remarks . — This is another of the northern echinoderms which just comes within the northeastern 
border of the Woods Hole region. Amidst the gravel and broken shells brought up in the dredge on 
Crab Ledge we found 4 small specimens of this species, the largest with the disk only 3 mm. across. 
The figure on plate 6 is taken from this specimen, enlarged. Apparently nothing is known of the 
habits or development of the species. 
3. Ophiopholis aculeata (Linnaeus). Daisy Brittle-Star. (PI. 5, figs. 24-27; pi. 7, figs. 41, 42.) 
Asterias aculeata Linnaeus, 1767. Muller, 1776. 
Ophiura bellis Fleming, 1828. 
Ophiocomabellis Forbes, 1839. 
Oph.wik.pis scolopendrica Muller & Troseliel, 1842. 
Ophiocoma aculeata Desor, 1848. 
Ophiopholis aculeata Gray, 1848. Verrill, 1866 and 1873. Lyman, 1882. 
Ophiopholis scolopendrica Stimpson, 1853. 
Ophiopholis bellis Lyman, 1865. 
Description. — Arms, 5; rather wide and flat. Diameter of disk, 15 to 20 mm. Length of arm, 60 to 
80 mm. Breadth of arm at base, without spines, 3 to 4 mm. ; with spines, 6.5 to 8 mm. Arm spines, 5 or 
6, of which the two middle ones are the largest ( 1 to 1.5 mm. long by 0.3 to 0.6 mm. wide), the upper one 
or two slightly, the lower two considerably, smaller, the lowest spine smallest of all; these spines are 
borne on a prominent vertical ridge on each side arm plate and stand at nearly a right angle to the arm. 
In adults these spines are very blunt, but in young individuals they are slender and acute. Beginning 
rather more than halfway out on the arms, the lowest spine becomes bent at the tip until finally it is 
little more than a sharp-pointed hook, usually with 1 or 2 minute teeth on the concave side. Disk 
circular, often bulging considerably between the arms, scaled, but more or less covered by a coat of 
very unequal granules, which are small and spheroidal near the center of the disk, and become much 
more prominent and spine-like on the interbrachial portions. In very few cases, however, does the 
granular coat cover the disk with even approximate uniformity. In the very great majority of 
specimens, from 6 to 36 more or less circular scales or plates are left, bare, and as these are always 
symmetrically arranged, the disk has a very ornate appearance. In the center is 1 plate, around 
which are grouped 5 others, placed radially; there are then 10 sets of 1, 2, or rarely 3 somewhat 
smaller plates, lying in rows radiating from the center, 5 radial and 5 interradial. In extreme cases 
the radial shields may also be left partially bare. Some or all of the plates are surrounded by definite 
circles of small granules. Upper arm plates nearly elliptical, about twice as wide as long; in large 
specimens those near the base of the arm are broken into two pieces. Each plate is surrounded by 
a single series of about 12 very large, somewhat angular, flat grains; but between any two adjoining 
upper arm plates there is only 1 row of these grains, so that those which serve as an anterior 
border for one plate are also the posterior border of the next distal plate. In some specimens, as 
the tip of the arm is approached, the bordering grains become more numerous and nearly circular, 
while in other specimens they are less numerous, so that the upper arm plates come in direct 
