208 
the articular surfaces are ratlier peculiar, but a detailed descriptiou 
thereof seems to me superfluous; I maj refer to the figures 6—9 
of PI. II. 
The affinities of this curious little Ophiurid are rather difficult 
to make out, the more so as the classification of the Ophiurids is, 
upon the whole, far from beiug satisfactorilj settled as jet. The 
covering of the disk recalls such forms as Ophiomastus and Ophio¬ 
typa, but much weight can scarcelj be laid upou this structure, 
as a similar plating is found quite generallj among joung Ophiurids. 
The armature of the mouth is similar in Ophiotypa, which appears 
also to lack the bursæ. On the other hånd Ophiotypa differs from 
Microphiura in having no radial shields, besides in the presence 
of dorsal arm-plates, of large tentacle scales in the whole length 
of the arm, and in having onlj one arm-spine, the joints being non- 
constricted. The arm-structure of Microphiura, on the other hånd, 
recalls the genus Opliiotrochus , which has, however, small dorsal 
plates; this genus has also grains on the disk and a somewhat 
similar armature of the mouth, but otherwise it differs from Micro¬ 
phiura in several iraportant characters (presence of bursæ, large 
radial shields etc.). To Ophiohelus, which it recalls in the curious 
structure of the vertebræ, Microphiura has scarcelj anj nearer 
relation. Upon the whole, Microphiura does not appear to be verj 
nearlj related to anj Ophiurid hitherto made known. 
The genus Microphiura maj be thus diagnosed: Disk verj 
small, covered with few large plates, the “primaries” being verj 
conspicuous, while the radial shields are verj small. Buccal shields 
nearlj verticallj placed. A single, large mouth-papilla to each side 
of mouth-angle; one tooth. No bursæ. Ventral plates well developed, 
dorsal arm-plates wanting. Spines smooth. Pores continuing to 
the end of the arm, the papillæ like the arm-spines, except that 
on the first pore. Vertebræ onlj partlj coalesced. The disk is 
verj easilj thrown off through autotomj. 
