THE ECH1NODERMS OF THE WOODS HOLE REGION. 
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bear low columnar elevations, each of which is crowned with a group of from 10 to 12 (more or less) 
delicate spines, 0.3 to 0.5 mm. in length. These spines are so short, and of such nearly uniform length, 
that the general impression in the living starfish is that of an almost smooth surface. In some 
specimens the spines radiate slightly from the top of the column while in others they are very closely 
erect. Along the sides of the rays, the columns tend to form longitudinal series, and 4 or 5 such series 
are sometimes well defined. On the actinal surface there is a well-marked series of plates forming a 
lateral margin to the ray. On the distal portion of the ray these plates are in contact with the 
adambulacral plates, but as the disk is approached, they diverge and form a margin for the actinal 
surface of the disk. The plates carry transverse ridge-like elevations, 0.5 mm. high (more or less), 
which are crowned by a group of 12 to 25 small spines, of nearly uniform length, arranged in a more 
or less perfectly double series. Actinal, interradial spaces, closely covered with plates, bearing low 
columnar or ridge-like elevations, crowned with clusters of spines somewhat larger than those of the 
abactinal surface. These clusters have a more or less definite arrangement, tending to form rows 
parallel to the adambulacral plates. The row adjoining the latter runs out about halfway to tip of 
ray, while the others are successively shorter, the interradial series being the shortest. Adambulacral 
plates with 2 series of spines, one in the furrow, and one on the face of the plate. Furrow series of 3 
spines in a row parallel to the furrow; 1 (or even 2) of these spines is often absent, but when all are 
present, the middle one is the longest (a little over 1 mm.), while the distal one is generally the 
shortest. Near the mouth these furrow spines are usually more or less fused at the base. Spines on 
face of plate somewhat pointed, 6 to 8 in number, 1 to 2 mm. long, arranged in a single curved 
transverse series, concavity of curve away from mouth; largest spine nearest furrow. Oral plates 
very prominent, bearing along the margin a series of 14 to 18 spines, of which those at the oral end of 
the plate are much the largest (2 to 6 mm. long), the next 1 or 2 pairs a little smaller, and the 
remainder markedly smaller. On the face of each plate is a ridge on which are borne 3 to 12 spines 
of very variable length; the longest are nearest the oral end of the plate and may be 2 to 3 mm. long. 
Papulae small, and generally single. Madrepore plate small, with numerous fine furrows. Feet 
biserial. Color in life, abactinally, dark red or deep rose-purple, rarely orange or dull yellowish; 
actinally, orange or yellowish of some shade. 
Range. — Greenland and Newfoundland to Crab Ledge, off Chatham, Mass., low water to 150 
fathoms; also on the coasts of Great Britain and Northern Europe; possibly circumpolar. 
Remarks. — This very striking and easily recognized northern starfish just enters the Woods Hole 
region, as we found it not uncommon on Crab Ledge. Of the 9 specimens we took, 4 have 10 rays, 
and 5 only 9. Both the largest specimen (220 mm. in diameter in life) and the smallest (40 mm.) are 
among the 9-rayed individuals. Little is known of the habits, and nothing of the development, of 
this species. 
OPHIUROIDEA. 
BRITTLE STARS, SAND STARS, SNAKE STARS, OR SERPENT STARS. 
The ophiuroids are a very large class, and the separation of nearly allied 
species is a task sufficient to test the skill of a specialist; but the Woods Hole 
region contains only 5 species, and these are so unlike each other that even a 
beginner can easily distinguish them. The terms which are used in describing a 
brittle star usually carry their own meaning, so that it is only necessary to introduce 
here a few of the less easily understood names: 
Adoral plates. — A pair of plates on the face of each of the 5 jaws, beside or in front of the oral shield. 
Oral pajnlLr. — Teeth-like projections along the edges of the jaws. 
Oral shield. — The large plate on the face of each jaw, near the base. 
Radial shields. — A pair of plates on the upper side of the disk, at the base of each arm; sometimes 
very prominent, again wholly covered. 
Tentacle scales. — Small scales on the lower side of the arm, on each side of the under-arm plate; 1, 2, 
or several at the base of each tentacle. 
Tooth papillse. — Small teeth-like projections at the point of each jaw. 
