348 BULLETIN 01 HIE 



i: open. Tcctli ten, very stout and uniform, except the lowest and 

 uppermost, which are smaller; all arc flat, a little longer than broad, 

 with a curved outer edge, coming to a point on the median line, nearly of 

 uniform thickness. Under the teeth are from one to three tooth-papillae 

 of irregular form. The joints of the arms arc easily seen, even in alcoholic 

 specimens, being" marked by the interior bones, which are indicated through 

 the skin. The arms themselves arc high and arched ; narrow below and 

 divided into ridges by the bases of the spines : they are even and without 

 depressions between the joints (except when the specimen is dried). The 

 arms keep a uniform size for some time, and then taper very gradually. 

 Arm-spines rounded, tapering, blunt, a little rough, but covered by the 

 skin ; there are two on nearly all the pores, but none on the first; one on 

 the second and third, and two on the fourth, whereof the upper one is 

 very small ; lengths to that of the arm joint, 1.2, 2.2 : 1.5. At the tip of 

 the arm both spines have three or four little hooks on their edge. Disk 

 with five pairs of narrow, prominent, radial ribs, which diverge from the 

 centre, where they meet, and run quite to edge, over the arms ; the mar- 

 gins of the disk are re-enteringly curved, and its sides slope from the upper 

 edge downwards towards the mouth region. The genital slits extend from 

 near the upper edge of the disk to the mouth-ring below. Over the whole 

 disk and arms are scattered microscopic thorny grains, which adhere lightly 

 to a thin epidermal coat, which seems to carry the coloring matter. In 

 alcohol the animal is of a dull flesh color, except the interbrachial spaces 

 on the sides of the disk, which are purplish brown. 



Variations. — A young one with a disk of 4.5 mm. had arms only one 

 half as loner as the specimen just described, to wit : 50 mm., from which it 

 appears that the arms increase in a greater proportion than the disk. The 

 teeth were only six ; the grains of the skin were less thorny and more 

 closely set than in the adult. Among many examined, the largest indi- 

 vidual had the disk 1 7 mm. in diameter, and thirteen teeth, of which the 

 two lowest were broken, so that each looked like two or three papillae side 

 by side ; below iheso there was a small single papilla. 



In l ■_'."> to 130 fathoms. 



Astrophyton mucronatum Lyman, sp. nov. 



Special Marks. — Radial ribs high, and beset with strong conical spines, 

 a few of which are also found as far out as the third fork on the upper side 

 of the arm. One madroporie body. 



,'/ cription of a Specimen. — Diameter of disk 39 mm. Length of arm 

 and distances of its forks from each other: — 



