REPORT ON THE CRINOIDEA. 



349 



are united by syzygy. The third radial therefore, being a hypozygal, bears no pinnule. 

 But the normal number of pinnules, one on each side of the ray, is still maintained ; for 

 the second radial, itself a syzygial joint, bears a pinnule on each side. 



The stem of this specimen, which is broken at the bottom, tapers slightly downwards, 

 and has tolerably regular internodes, with five cirri at each node in the usual way. 

 The stem of the other individual, however, does not decrease in size at its lower end, 

 which terminates in a nodal joint with a freshly exposed under surface. The inter- 

 nodes of this stem are very irregular in length, and generally consist of one or two joints 

 more than in the smaller specimen, while the development of cirri at the nodes is 

 extremely irregular. No less than ten of the thirty-three remaining nodes have one or 

 more cirri deficient, as shown in the following Table : — 



In the lower part of the stem there is no trace of the absent sockets, which are replaced 

 by ridges like those on the internodal joints ; but in the middle and upper parts the 

 socket is present, though imperfectly developed, especially at the fifth node. At the 

 thirteenth, the place of the socket is entirely taken up by a group of sessile Cirripedes 

 ( Verruca). 



3. Aletacrinus murrayi, n. sp. (PI. XLI. figs. 12-17 ; PI. XLIL). 



Dimensions. 



Length of stem to eighteenth node, ..... 184'00 mm. 



Diameter of stem, . ....... 6'75 ,, 



Longest cirrus (forty-eight joints), ...... 43-00 ,, 



Diameter of oalyx, . . . . . . . . 1 1 '00 „ 



Diameter of disk, . . . . . . . . 21-00 „ 



Length of arm (one hundred and fifteen joints above tertiary axillary), . 100-00 „ 



Length of pinnule on second radial (fifteen joints), .... 18-00 „ 



Length of first palmar pinmile (seventeen joints), . . . .23-00 „ 



Length of first pinnule after tertiary axillary (eighteen joints), . . 14-00 „ 



Description of an Individual. — Stem robust and of a rounded pentagonal form, wdth 

 very shallow re-entering angles. Internodes composed of thirteen joints, wdth smooth 

 sides and faintly crenulated edges. The supra-nodal joints are slightly incised, but the 



