MUSEUM OF COMPARATIVE ZOOLOGY. 337 



Ophiophragmus are distinguished, not by the chewing apparatus, but by 

 the covering of the disk. The former has four species, — 0. hispida Lym., 

 brachiala Lym., 0. scabriuscula Lym., 0. olivacea Lym.* The latter has 

 five species, — 0. septus Lym., 0. Wurdemani Lym., 0. marginatus Lym., 

 O. antarcticus Ljn., O. gibbosus Ljn. 



Finally, to complete that part of Miiller and Troschel's genus Ophiolepis, 

 which centres in Amphiura, we must mention Ophiosligma and Ophiactis. 

 The latter approaches Amphiura in one direction (G>. Krebsii), Ophiopholis 

 in another (0. Kroyeri), and Ophiacantha in a third (0. clavigera). See 

 description of Ophiactis humilis. 



Amphiura pulchella Lyman, sp. nov. 



Special Marks. — Six mouth-papillfe to each angle, the inner pair thick 

 and running upward to the teeth. Radial shields very narrow, and closely 

 joined for nearly their whole length. 



Description of a Specimen. — Diameter of disc 3.2 mm. The arm was 

 broken off at 21 mm., but had apparently been about 28 mm. long. 

 Mouth-papillae three on each side, all on the mouth-frames ; the two 

 outer ones small, rounded, and scale-like ; the innermost one thickened 

 and running upwards to the teeth. Mouth-shields longer than broad, rather 

 narrower within than without. Side mouth-shields very narrow within, 

 where they meet ; much broader without, where they touch the minute 

 first under arm-plate with their corner. Under arm-plates separated ; as 

 broad as long, pentagonal with the angle inward ; lateral sides re-enter- 

 ingly curved ; outer side nearly straight on the first three or four plates ; 

 beyond that, with a decided notch in the outer side. Side arm-plates 

 meeting below and (after the second joint) above also; the separation, how- 

 ever, of the upper and under plates is narrow ; length of third plate 

 .2 mm. Upper arm-plates broader than long, of an oval form, with the 

 inner curve greater than the outer. Beyond the second joint they are 

 slightly separated. Disk closely covered with minute imbricated scales, 

 of which there are about 100 to a square mm., where they are smallest, on 

 the upper surface. In the centre is a distinct circle of five round primary 

 plates, with a sixth in the middle. Radial shields narrow, and sunk in the 

 disk, joined for their entire length closely, except just at their inner 

 extremities; length to breadth .9 : .2. Arm-spines three; short, smooth, 

 rounded, tapering, nearly equal ; lengths to that of under arm-plate .3, .3, 

 .3 : .2. One small, nearly circular tentacle scale. 



Color, in alcohol, disk greenish gray, arms lighter. 



In 39 fathoms. 



* To these should apparently be added Ophiophragmus Loveni Ljn. and 0. echinatus 

 Ljn. Why he placed them thus, and still admitted the genus Ophiocnida, is not clear. 



