new Starfish and new Brittle Stars. 119 
Ophiacantha similis, sp. n. 
This species is very nearly related to O. moniliformis, 
Liitken and Mortensen, from which it differs in the following 
particulars :— 
The oral shields have an evenly curved distal border, 
quite without the process so characteristic of O. moniliformis, 
and a proximal border which is either a straight line or two 
gently concave lines meeting in the centre to form a point 
between the bases of the side mouth-shields. 
The side mouth-shields are much larger than those of 
O. moniliformis, and very different in shape; their internal 
apposed edges are unusually long; on reaching the oral 
shield these turn abruptly and run in a slightly curved, 
sometimes almost straight, line to the first under arm- plate ; 
frequently the distal borders of the side mouth-shields, 
which are about as long as the apposed borders, are approxi- 
mately straight, making a right angle with the latter ; the 
outer borders make a regular curve from the inner apposed 
blunted apices to the outer, similarly blunted, apices, which 
are in contact with the distal portion of the first under arm- 
plate. The side mouth-shields therefore resemble in shape 
stout crescents with blunted ends or boomerangs. They lie 
entirely within the lateral angles of the oral shields. 
The mouth-papille are slightly shorter and stouter than 
the corresponding structures in 0. moniliformis. 
One or two tooth-papille are exceptionally present. 
The teeth are much broader than those of O. moniliformis. 
The side arm-plates are markedly shorter than in O. monili- 
formis, and the arm-segments are much less swollen distally ; 
the arm-spines, five or six in number, are much shorter than 
those of O. moniliformis and noticeably stouter. 
Type. Cat. no. 385838, U.S.N.M., from ‘ Albatross ’ 
Station 2818, among the Galapagos Islands, in 892 fathoms. 
Ophiolebes mortenseni, sp. 0. 
The diameter of the disk, which is rounded-pentagonal, is 
5°5 mm. 
The disk is covered with moderately large scales of very 
uniform size, each of which bears a short cylindrical stump 
terminating in a tuft of thorns. There is sometimes to be 
seen on oue or both sides of the arm-bases a narrow linear 
streak free of scales and stumps, which indicates the position 
of the radial shield. The disk closely resembles that of 
O. vestitus, Lyman, but the processes are cylindrical with 
