REPORT ON THE CRINOIDEA. 331 
1878. Pentacrinus Miller’, Agassiz, Bull. Mus. Comp. Zoil., vol. v., No. 6, p. 56. 
1879. Pentacrinus Miilleri, Pourtalés, Bull. Mus. Comp. Zodl., vol. v., No. 9, p. 214. 
1879. Pentacrinus Miilleri, Agassiz, Bull. Mus. Comp. Zodl., vol. v., No. 14, p. 296. 
1882. Pentacrinus decorus, P. H. Carpenter, Bull. Mus. Comp. Zoil., vol. x., No. 4, p. 171. 
Dimensions. 
Greatest length of stem, to fiftieth node, : : A : . 80:00 cm. 
Diameter of stem, . : 4 E : : 5 j 4-75 mm. 
Longest cirrus (thirty-two joints), . : . : ; AOU ee 
Diameter of calyx, . . 3 . 5 : é : ; 8:00) 5 
Diameter of disk, : é : : : A 3, elZeoOn fy, 
Length of arm (one hundred joints), : é : : He FS0:00) 15; 
Length of distichal pinnule (thirteen joints), ¢ : ; gj) ISSO 
Length of pinnule from lower third of arm (twenty joints), . : ee 6:00) 8, 
Stem moderately slender and usually smooth, with a rounded pentagonal outline. 
Seven to sixteen (usually eleven or twelve) internodal joints, with much crenulated 
edges. Nodal joints somewhat enlarged, expanding from above downwards to the top 
of the cirrus-sockets. These are deeply hollowed, and have a pear-shaped form, being 
continued downwards as well marked grooves on to the infra-nodals, Cirri small and 
slender, rarely composed of more than thirty joints, the first six of which are quite short. 
and the remainder squarish or slightly elongated, with a moderately smooth dorsal edge. 
Terminal claw small, with no opposing spine. Lowest limit of the interarticular pores 
between the ninth and eleventh nodes. 
Basals very variable, sometimes quite small, inconspicuous, and isolated ; but 
presenting all gradations from this condition up to that of large triangular knobs 
standing out prominently from the general plane of the calyx, and meeting one another 
by their extended lateral angles. 
The two outer radials united by bifascial articulation. The rays and their sub- 
divisions sometimes separated by plated perisome, and sometimes in close apposition ; 
but the sides of the lower arm-joints are scarcely flattened at all. Ten to twenty-five 
arms. Primaries of two to seven distichal joints. When three or more distichals are 
present the first two are united by bifascial articulation, the second bearing a pinnule, 
while the third or sometimes the axillary is a syzygy. But if there be only two 
distichals, and the axillary be a syzygy, the first bears a pinnule and is united to the 
second by muscles. Lastly, if the axillary be not a syzygy, there is a bifascial articula- 
tion between it and the first distichal. Secondary arms (when present) of one to nine 
palmar joints, which vary in character as in the primary arms, though to an even 
greater extent. If the arms become free at the radial axillary the first syzygy is usually 
on the third brachial; but if the primary arms divide there is generally a syzygy in the 
second free brachial, though not unfrequently it occurs between the first and second. The 
