178 .BULLETIN OF THE 



Sir Wyville loft it an open question whether the articular facets on 

 tlie upper edge of the calyx-tube belong to the first or to the second 

 radials. I believe myself that they are of the former nature, partly on 

 account of their great resemblance to those of certain fossil species, and 

 partly because the axillaries appear to me to be syzygial or double 

 joints. 



Sir Wyville has pointed out that the cup exhibits a very marked di- 

 vision into bivium and trivium ; for " one side of the border is much 

 thicker and considerably higher than the other side, and the three arms 

 articulated to it are much lai-ger than those articulated to the oppo- 

 site side." In fact, the three facets of the trivium are themselves 

 une(|aal, the centre one being both longer and wider than the other two, 

 which are themselves longer and a little wider than the two facets of the 

 bivium. This want of symmetry in the calyx is very remarkable, as 

 it is precisely similar to that described by De Loriol * in Eugeniacrinus 

 mai/alis, from the Leptcena bed (Middle to Upi)er Lias) of Calvados in 

 Normandy. The calyx of this species, formed by the five contiguous 

 radials, tapers away downwards to a truncated extremity, which De 

 Loriol supposes to have rested on the top stem-joint, basals being appar- 

 ently absent. 



liut although Eugeniacrinus mayalis probably had a short stem, it is 

 certainly very closely allied to Holopus. The calyx as well as the second 

 and third radials are covered with scattered granules of variable size, just 

 as in Hnlopus. The two outer radials were united by a muscular joint ; 

 but in a closely allied species, E. deslongchampsi, which is more symmet- 

 rical and less coarsely granular than E. mayalis, they are luiited by 

 syzygy, just as I believe to be the case in Ilolojnis. Together with the 

 calyces and separate radials of these two species, the Leptcena bed con- 

 tains a large number of isolated arm joints,! some of which are extraor- 

 dinarily like those forming the lower part of a Holojms arm. 



One reason why I suspect the axillaries of Holopus to be syzygial 

 joints is as follows. In one individual the axillaries on the two rays of 

 the bivium are distinctly in two parts, though the sutural lines do not 

 extend right across them. On the three axillaries of the trivium, how- 

 ever, no sutural lines are visible at all ; though they are just traceable 

 in another specimen, and are fairly distinct in a young one 8 mm. high. 



The condition of the very young individual which was obtained by 

 the " Blake " at Station 22, and was figured in Volume V. No. 9 of the 



* Paleontologie rran9aise. Terraiu Jurassique, Tom. XL p. 78, PL VIIL figs. 1-5, 

 t Loc. ciL, PL XI. 



