62 p. n. CARPENTER ON COMATULiE FROM 



The coiitrodorsal bears no trace of cirrhus-sockets, and peripherally 

 is almost, but not quite, on a level with the radials. Its surface 

 rises a little from the periphery towards the centre, and then sinks 

 again. The larger portion of the dorsal surface is thus somewhat 

 concave, and the hollow is partially filled up with pyrites. The 

 radial clefts are very marked, but are chiefly due to the inner edges 

 of the radials being concave instead of straight, as the sides of the 

 centrodorsal are much less curved than in Phanofjenia or Act. 

 stellata. Hence its outline is only very bluntly stellate. The first 

 radials are thus very much shorter in the middle than at the sides 

 along their lines of suture, the inner ends of which are in contact 

 with the points of the centrodorsal star. The distal edges of the 

 first radials are also somewhat incurved and receive the convex 

 proximal edges of the second radials ; these, as well as the 

 axillaries, are rather arched from side to side. They are twice as 

 long as the first radials (along their middle line), have a nearly 

 straight distal edge, and are only partly united laterally. The 

 axillaries are broadly pentagonal and about half as long again as 

 the second radials ; the first brachials oblong and partly united 

 laterally, the opposed inner faces of each pair having small fossae 

 which lodged the ligament connecting them. The articulation 

 between them and the second brachials was by ligaments attached 

 on either side of a vertical ridge as in Ant. rosacea. The second 

 brachials are bluntly wedge-shaped and rather convex, their distal 

 articular faces having the usual fossse for muscles and ligaments, 

 and a large pinnule-socket towards the outer side. 



Total diameter across the circle of second brachials 21 millims. 

 Diameter of centrodorsal plate 5 millims. 



Locality. The Gault of Folkestone. Original in the Woodwardian 

 Museum, Cambridge. 



EemarJcs. The chief interest of this fossil is that it shows the same 

 altered condition of the centrodorsal as we now find in Actinometrce 

 from the Philippines and the Malay Archipelago, all of them from 

 quite shallow water, i. e. 20 fathoms or less. 



I have much pleasure in dedicating this fine species to Prof. Lovcn, 

 whose description of Plianogenia has helped me greatly towards 

 understanding the peculiar features which it presents. 



6. Antedon rotunda, n. sp. Plate Y. fig. 5. 



Centrodorsal hemispherical, slightly flattened at the pole, which 

 is free from cirrhus-sockets and marked by a shallow stellate im- 

 pression. Sockets polygonal, closely set in four alternating rows 

 with occasional traces of a fifth and even of a sixth. Ventral sur- 

 face very slightly concave, with a markedly circular outline, and a 

 faintly lobulated axial opening leading into a shallow central 

 cavity. Basal grooves rather wide, with rounded distal, and bluntly 

 pointed proximal ends. Central ends of radial areas occupied by 

 small shallow pits lying a little way from the margin of the axial 

 opening. 



Diameter 4*5 millims. ; height 2 millims. 



