THE EOHINODERMS OF THE WOODS HOLE REGION. 
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more or less finely mottled with whitish, the lower surface yellowish. Outer ends of radial shields 
almost always very light, giving the appearance of a white spot at the base of each arm. Very young 
individuals have the disk bright orange. 
Range . — Arctic Ocean to New Jersey, low water to 60 fathoms. Also on the coast of Europe well 
into the Mediterranean. Lyman reports specimens even from near the Cape of Good Hope, 98 
fathoms, and near Australia, 120 fathoms, but these probably represent species which in life would 
show marked differences from squamata. 
Remarks . — This is the commonest and most widely distributed of the opliiurans in the Woods Hole 
|, region. It is common in Vineyard Sound, especially just east of Nobska, and is reported abundant at 
Newport. We also took it at Crab Ledge and off Sankaty Head, and specimens were brought in from 
Ram Island and the Eel Pond at Woods Hole. The latter were very small, and were found on the eel 
grass. I am indebted to Dr. Id. F. Perkins for one of these, a beautifully stained and mounted specimen 
with disk half a millimeter in diameter. Adults occur on rocky or shelly bottom and generally are 
found in the interstices and cavities of the stones and shells. The breeding season is in the summer, 
and in July and August the adults nearly always contain eggs or young, for, as is well known, this 
species is viviparous. Often one of the interbrachial spaces will be found swollen and of a slightly pink 
shade. If opened, it will be seen to contain the bright pink eggs of a parasitic crustacean. The eggs of 
the brittle star are yellow, orange or reddish. The development of this species is without metamor- 
phosis and has been studied in part by several observers in Europe and by Fewkes (’87) in this 
country, but much still remains to be done. Fewkes’s paper contains interesting notes on the breeding 
and other habits of adults. 
5. Gorgonocephalus agassizii (Stimpson). “Basket Fish”; “Spider.” (PI. 6, figs. 35, 36; pi. 7, 
figs. 45-47.) 
Euryale scutatum Gould, 1841 (not of Blainville). 
Astrophyton agassizii Stimpson, 1853. 
Gorgonocephalus agassizii Lyman, 1882. 
Description . — Arms 5, dividing dichotomously, but unequally, 11 to 15 times, and perhaps more; 
branches of unequal length, and alternating, so that if the left-hand branch of the first fork is the 
longer, the right-hand branch will be longer at the next fork, the left hand at the third, the right hand 
at the fourth, and so on. Disk 40 to 80 mm. in diameter; length of arm 140 to 280 mm.; breadth of 
arm at base 8 to 10 mm.; at first fork 10 to 18 mm. True arm spines wanting (Lyman). Disk more 
or less flattened, with radial shields very prominent as raised ridges, covered with a thick skin, which 
is usually quite smooth, but often bears granules or low blunt spines, sometimes in large numbers, 
especially at the center of the disk. Margin of disk sharply defined by a band of plates connecting lire 
outer ends of the radial shields. The latter are long and narrow and nearly meet at center of disk; 
although sometimes nearly smooth, they usually bear numerous knobs or thick, blunt spines, a milli- 
meter high, more or less. Upper surface of arms beautifully curved; on the last few subdivisions there 
is a faint longitudinal groove; the surface may be smooth near the base and along the sides for some 
distance, though generally covered with coarse granules which are at first irregularly disposed, but after 
about the second or third fork begin to form incomplete rings about the arm. After about the sixth 
fork the granules are confined almost wholly to these rings, which soon become raised ridges, about 
2 granules wide. Undersides of arms nearly flat, smooth, the numerous small, irregular underarm 
plates quite evident in dry specimens. Tentacle scales usually 3, sometimes 4, at base of arm 2 or 1; 
the first tentacle pore has none. These scales are spine-like, and about a millimeter long. Near the 
tips of the arms there are only 2 or even 1, but there they assume the form of little, toothed hooks. 
No oral shields or adoral plates, but the jaws are surrounded by a wide circle of calcareous plates 
connecting the bases of the arms. Teeth, teeth papilla 1 , and mouth papillse, all alike and spiniform, 
about 20 in number on each jaw, and about 2 mm. long. Interbrachial spaces nearly triangular with 
a rounded point inward, covered with a thick, smooth, or more or less granular skin, and containing a 
single pair of genital openings near their outer edges. At the inner point of one of the interbrachial 
spaces is the single, large madrepore plate, which is wider than long. Color in life, disk and interl irachial 
spaces brown, of variable shade, but usually dark; radial shields often lighter; arms cream color, yellow, 
brownish-yellow, or reddish; some specimens have a very strong reddish cast. 
Range . — Arctic Ocean and Gulf of St. Lawrence to Crab Ledge, off Chatham, Mass., and perhaps 
even on Nantucket Shoals, Also reported from Vadso, Norway. Low water to 800 fathoms. 
F, O. B. 1902—36 
