162 Dr. F. A. Bather— A Neiv Ophmrid 



The relations of the wings are perhaps most clearly shown in the 

 eighth segment ; here the outer corners of the distal wings seem to 

 overlie processes from the median body (c in Fig. 1). The 

 transverse separation of the median body of one segment from that 

 of the next is not very clear. In the distal part of the ray there 

 are indications of a separation not only between the segments, but 

 between the two halves of each segment. The median bodies are 

 slightly grooved on the ventral surface, so that a continuous open 

 groove runs the whole length of the preserved portion of the ray, 

 and passes into the radial angles of the oral skeleton. 



Kay V is in a different state of preservation, having appai'ently 

 been somewhat twisted over on to the side that lies on the right 

 in the figure, so that the ventral groove, which in its proximal 

 I'egion is median, is seen on the right in the distal region. In 

 the preserved portion of the ray the existence of four distinct 

 segments is pretty clearly indicated by transverse ridges and 

 indentations, also by two spines, one at the distal end of the third 

 segment, the other at the end of the fourth, both on the left-hand 

 in the figure. Apparently there are here preserved only the median 

 bodies, a fact which might suggest that they were distinct elements 

 from the side-wings. There are, however, traces of the wings on 

 the left of the second and third segments. In none of these 

 segments is there a clear indication of a subsidiary transverse 

 division. 



The other rays are too incomplete to throw any light on the 

 structure of the segments, but in their proximal segments the side- 

 wings are to be distinguished, especially in ray iv. 



The oral skeleton (Fig. 3) is divisible into five radial portions, 

 each of which is bilaterally symmetrical about the radius, and at 

 first sight appears to consist of two curved bars or syngnaths 

 enclosing a lanceolate space, of which the apex is distal, while the 

 proximal ends of the bars approach closely those of the adjacent 

 bars on each side. More minute examination shows that each of 

 the supposed curved bars consists of three elements, to which may 

 be applied the terminology adopted by Dr. J. W. Gregory, the distal 

 element being a ' mouth-frame,' the proximal one a ' tooth,' and the 

 intermediate one a 'jaw.' Of these tlu'ee elements the jaws are 

 the longest, and broaden at their distal ends ; the distinction between 

 them and the mouth-frames is marked either by a sharp bend or an 

 actual gap. The mouth-frame is about two-thirds the length of the 

 jaw; each pair is joined distally to the median body of the proximal 

 ray-segment. The teeth also are distinguished from the jaw by 

 a sharp bend at the point of union, while they lie a little above the 

 jaw as one views the specimen from the ventral surface. There 

 is no sign of a 'jaw-plate' or 'torus angularis'; there may have 

 been a small one, or the structures here called ' teeth ' may represent 

 primitive unfused elements of the torus, such as have been observed 

 in the development of recent Ophiurids. Fewkes states that in 

 AmpJiiura the teeth grow out from the torus and have no independent 

 centres of calcification. 



