552 BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Key to the Asteroids of the Woods Hole region. 
Rays rough and spiny, since the meshes of the skeletal network are coarse and bear prominent spines, 
singly or in groups of 3 or 4; pedicellariae numerous; feet in 4 longitudinal rows in each 
furrow. 
Adults usually over 100 mm. in diameter; papulae numerous in small groups. 
Rays tending to be cylindrical and blunt; skeleton quite firm; spines rather few and coarse; 
pedicellariae on adambulacral spines short and blunt; madrepore plate usually bright orange. Asturias forresi 
Rays tending to be somewhat flattened and acuminate; skeleton open and rather soft; spines 
numerous, tending to form a noticeable median longitudinal row on the abaetinal side of 
each ray; pedicellariae on adambulacral spines numerous, long, slender, and sharp; madre- 
pore plate pale Asterias vulgaris 
Adults usually much less than 80 mm. in diameter; papulae few, 1, 2, or 3 in a place. 
Rays tending to be cylindrical and tapering; skeleton moderately firm, with numerous spines; 
pedicellariae very numerous, especially on actinal surface, forming wreaths, generally very 
noticeable, on the spines there Asterias tenera 
Rays decidedly flattened, rather wide and blunt; skeleton coarse and very firm; spines few; 
pedicellariae on adambulacral spines few and blunt, but a prominent series of them just 
within the edge of the ambulacral furrow Asterias austera 
Rays rather smooth, since the meshes of the skeletal network are fine and bear numerous very small, 
delicate spines; no pedicellariae; feet in 2 rows — 
With 5 or G rays Cribrella sanguinolenta 
With 9 toll rays Solaster endeca 
1. Asterias forbesi (Desor). Common starfish. (PI. 1, figs. 1,2; p). 4, figs. 14,15.) 
Asteracanthion forbesi Desor, 1S48. 
Asterias arenicola Stimpson, 1862. 
Asteracanthion berylinus A. Agassiz, 18(13. 
Asterias forbesii Verrill, 1866 et seq. 
Description . — Rays normally 5, occasionally 6, rarely 4 or 7. R=75 to 130 mm., r=10 to 25 mm., 
R=4.5 to 8 r. Breadth of ray, near base, 15 to 30 mm., R=3.5 to 5 br. Rays stout, blunt, and some- 
what rounded at the tip, abaetinal surface normally arched. Risk moderate or large, often highly 
arched. Interbrachial arcs rather acute. Abaetinal area covered with stout plates, closely soldered 
together into a firm skeleton, with no constantly regular arrangement. These plates carry single 
prominent spines, 1 to 2 mm. high, which are usually blunt and minutely rough or thorny at the tip, 
but in young individuals may be quite sharp. About the base of these large spines are often grouped 
2 to 4 smaller ones, 0.5 to 1 mm. high, also blunt. All the spines are more or less fully encircled 
about midway between base and tip with a cluster of very small, blunt pedicellariae. Scattered more 
or less freely all over the abaetinal surface are pedicellariae a little less blunt and somewhat larger. 
Sides of rays well rounded, but oftentimes with a well-defined longitudinal arrangement of spines, 
about halfway between actinal and abaetinal surfaces. Below this row is a space of very variable width 
which is usually free from spines but bears a few scattered pedicellariae. Beneath this space, and well 
on to the actinal surface of the ray is a prominent longitudinal series of plates, each of which bears an 
obliquely arranged pair or trio of very prominent spines (like those of the abaetinal surface, and 
wreathed by pedicellariae in the same way), of which the most distal is nearest the ambulacral furrow. 
This series is usually clearly defined, but in some individuals it is more or less irregular. Between it 
and the adambulacral spines is a longitudinally extended space, which may be perfectly open and occu- 
pied by only a few pedicellariae, but in many specimens is obliterated by a single series of large spines, 
which are more or less square cut or even clavate at the end, and are often slightly beveled on one side. 
The presence or absence of this row is not a matter of size, but it is very probably a matter of age, though 
that is not yet proved. Adambulacral plates with 1 or 2 (usually 2) rather long (2 to 4 mm. ), somewhat 
flattened and slender spines square cut or blunt at the end, and many of them, especially near the 
mouth, bearing small blunt pedicellariae, though these are often wanting in young individuals. In 
a specimen with R=24 mm. there are about 60 adambulacral plates on each side of the ambulacral fur- 
row; in one with R=67 mm. there are about 100; and in one with R=80 mm. there are about 130. 
Oral spines not peculiar. Papular areas variable in size, but usually large, with numerous papulae, 
generally 5 or more in each group. Madrepore plate of moderate size, 2 to 5 mm. in diameter, with 
numerous narrow furrows, and not surrounded by any special circle of spines. Tube feet quadriserial, 
crowded. Color in life very variable; the most common shades are brown, purple, orange, green, and 
bronze. Spines generally light and madrepore plate usually bright orange-red. After death the 
bright tints are generally lost and in preserved specimens the madrepore plate is usually yellow or 
brown. 
Range . — Maine to the Gulf of Mexico, rare or local north of Cape Ann; low water to 27 fathoms. 
