REPORT ON THE ASTEROEDEA. 1 1 1 



The paxillae of the abactinal area are roundly hexagonal, tabulate, and closely placed, 

 usually with about a dozen short, roundly truncate, polygonal granules, those occupying 

 the central portion of the tabulum being a shade larger than the rest, whilst some of those 

 at the extreme margin are very small. The primary apical plates (basals and first radials) 

 are distinguishable and bear the largest paxillae on the disk, the other paxillae diminish 

 slightly in size as they approach the margin and proceed along the ray. The paxillae 

 are arranged in regular longitudinal lines parallel to a series which occupies the median 

 dorsal line, and which are rather larger than the rest. A considerable number of inter- 

 mediate plates (paxillae) are present between the dorso-central plate and the five " basal " 

 plates, the position of these being at about one-third of the distance from the centre to 

 the margin. The madreporiform body is comparatively large, and lies external to, and 

 independent of, the adjacent basal plate, which is little more than half its size. 



The marginal plates form a well-rounded lateral wall, the cuiwature of which is 

 semicircular in section. The supero-marginal plates are twenty-eight to thirty in number 

 from the median interradial line to the extremity. In the interbrachial arc the height 

 of the plates is about twice their length, but on the outer part of the ray the height is 

 relatively less. The breadth of the marginal border, as seen from above, is also somewhat 

 greater in the interbrachial arc than out upon the ray. The supero-marginal plates are 

 covered with a closely packed polygonal granulation. The granules are short and flatly 

 truncate, and are twice as large on the inferior half of the plates as on the superior. No 

 prominent spines are present on the supero-marginal plates. 



The infero-marginal plates correspond to the superior series, but extend rather further 

 on the actinal area than the superior plates do on their area. The granulation of the 

 inferior series has a marked tendency to become squamiform, especially on the inferior 

 portion of the plate where it is much smaller. On the portion of the plate adjacent to 

 the superior series are usually one or two granules larger and more prominent than any 

 of the others. In the interbrachial arc three short, tapering, sharply adpressed spines 

 stand at well spaced distances on the median line of the plate ; but out upon the ray 

 seldom more than one is present. 



The armature of the adambulacral plates consists of a furrow series of rather elongate, 

 delicate spines, six in number, which increase in thickness towards their free extremity, 

 and are roundly truncate. External to these is a longitudinal series of three spines, rather 

 widely spaced, shorter than the furrow spines, but rather more robust and tapering ; and 

 these again are followed by two series of four spines, which are shorter and more closely 

 placed, and usually regular within the disk, but subject to some confusion on the outer 

 part of the ray. 



The first series of actinal intermediate (ventral) plates adjacent to the adambulacral 

 plates present a remarkable arrangement of granules. These stand in three or four regular 

 lines, transverse to the furrow, the two lateral series on each plate being inclined slightly 



