328 THE VOYAGE OF H.M.S. CHALLENGER. 
This condition recurs over a length of three internodes on the remaining stem-fragment, 
the sockets gradually becoming more and more obscured; and at the lowest node the 
incrustation seems to have completely overgrown the bases of the cirri, nothing appear- 
ing to indicate their presence but minute uregular stumps. Fifty joints lower down 
the stem terminates in a flattened expansion by which it was probably attached. The 
abnormal condition of this stem is interesting from its resemblance to that presented by 
a specimen of the fossil Millericrinus pratti, which I have described elsewhere.2 In 
this case, however, the secondary deposit of limestone which is outside the uppermost 
stem-joints is divided up into segments not corresponding with those enclosed by it. 
7. Pentacrinus blakei, P. H. Carpenter (Bis) XOCKT XX, = SP eRe 
figs. 1-3). 
1882. Pentacrinus blakei, P. H. Carpenter, Bull Mus. Comp. Zoil., vol. x. p. 172. 
Dimensions. 
Total length, ; ° ; : =) 2scorem: 
Longest stem, anaes off at oe enty- etl rae é 5 : - 1600 mm. 
Diameter of stem, : 5 : : j : : 4:0! =, 
Longest cirrus (twenty-nine ani) : . : ; : Sigh Linas 
Diameter of calyx, . : 3 ; : : 60 °,, 
Length of arm (one hundred aa tive qe) ; nS : : a L20:05 5 
Length of pinnule on first distichal (eighteen joints), . . : : HU) 
Length of pinnule from middle of arm (twenty joints), ; : Eales 
Stem slender and smooth, with a rounded pentagonal outline ; five to seven inter- 
nodal joints with distinctly crenulated edges. Nodal joints high, not projecting out- 
wards between the cirrus-facets, which are comparatively small and circular, and do 
not nearly reach their upper edge. Infra-nodals more or less grooved to receive the 
chrus-bases, so that the sockets appear to have pyriform downward extensions of 
variable size. Cirri small and slender, of twenty-five to thirty joints, the first six of 
which are quite short, and the remainder squarish with a tolerably smooth dorsal edge. 
Terminal claw small, with no opposing spine. Lowest limit of the interarticular pores 
between the sixth and tenth nodes, 
Basals small, triangular, and more or less rounded, well separated laterally by the 
lowest parts of the rather high radials. The rays and their subdivisions moderately close, 
without any intervening perisome, but scarcely flattened at all except just on the lower 
brachials. The two outer radials and lowest distichals respectively united by bifascial 
articulation, The third radials and the second distichals project backwards into the middle 
of the preceding joints, their proximal surfaces being somewhat deeply hollowed from side 
to side, and slanting downwards and backwards. About twenty arms, usually only 
1 Quart, Journ, Geol. Soc., vol. xxviii. p. 33, pl. i. tig. 21. 
