p. H. CAEPENTER ON CRETACEOUS COMATUL^. 549 



40. On some new Cretaceous Comatul^. By P. Herbert Carpenter, 

 M.A., Assistant Master at Eton College. (Read June 23, 1880.) 



(Communicated by Prof. P. M. Duncan, M.B. Lond., F.E.S., V.P.a.S.) 



[Plate XXIII.] 



In the following pages I have described some new Cretaceous Coma- 

 tulce which have been placed at my disposal for this purpose since 

 the publication of my paper on British Secondary Comatulce in the 

 February Number of this Journal (vol. xxxvi. pp. 36-55, pi. v.). 



Two of the new species belong to the cabinet of the Rev. P. B. Brodie, 

 M.A., F.G.S., who courteously offered them to me for description. 

 The other three are in the Geological Collection of the British 

 Museum, and (as before) I am indebted to the kindness of Dr. Henry 

 Woodward, F.R.S., and of Mr. R. Etheridge, Junr., for the oppor- 

 tunity of examining them. To all of these gentlemen my best 

 thanks are due. 



1. AnTEDON PERFORATA, n. sp. (PL XXIII. fig. 2.) 



The centrodorsal is a thick pentagonal disk with steep sides and 

 a hollowed dorsal surface (fig. 2, b). At the bottom of the hollow 

 is an irregular central opening, and on its sloping sides are five others, 

 radially disposed and separated by faint grooves. There are about 

 fifty deep cirrhus-sockets, arranged rather irregularly ; those which 

 are best preserved show traces of striated margins and have small 

 articular ridges crossing them at or slightly above the middle, which 

 are pierced by the transversely oval openings of the cirrhus-canals 

 (fig. 2, c). The ventral surface (fig. 2, a) is marked by various pits 

 and hollows, hut is tolerably flat on the whole, except that one of 

 the radial areas falls away very much toward the periphery. The 

 basal grooves are indistinct, with nearly parallel sides, which show 

 faint traces of plication here and there ; and the central cavity is 

 irregularly five-rayed, with uneven margins and slight indications of 

 radial ribs on its walls like those of ^.^arac?Oira,thestronginterradial 

 ribs of which are absent in this specimen. 



Diameter 11 1 mm. ; height 5 mm. 



Locality. The (Upper) Chalk, Margate. Wetherell Collection, 

 British Museum. 



Remarks. The somewhat worn specimen described ahove resem- 

 bles A.joaradoxa in general appearance, but lacks the keyhole-shaped 

 opening in the cirrhus-sockets characteristic of this species and of 

 A. rugosa (fig. 4). One socket, it is true, has a central somewhat 

 keyhole-shaped pit ; but I believe this to he artificial. The rim 

 around the opening of the axial canal has been worn away, and the 

 opening thereby united with the deepest part of the dorsal ligament- 

 pit which lies just beneath it; while the two disconnected ends of 

 the articular ridge stand up on either side of the composite pit thus 

 produced, so that the socket has somewhat the appearance of those 



