1034 DR. J, W. GREGORY ON THE CLASSIFICATION _[ Dee. 15, 
Type species.—Bundenbachia beneckei, Stiirtz. 
Remarks.—The diagnosis of this genus is based on specimens in 
the British Museum received from Herr Stiirtz. The diagram 
(fig. 4) has been prepared from specimen B.M. No. E 3495. 
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Bundenbachia: arm-structure. 
Bundenbachia differs from Protaster by the irregular nature 
and soft plating of the disc, by the presence of spine-bearing 
plates attached to the adambulacral ossicles, and by the different 
form of the ambulacral ossicles. 
Family 2. PALHZOPHIURIDA, 
Diagnosis—Lysophiure in which the ambulacral ossicles are 
long and bar-shaped, with the longer axis parallel to the arm. 
Remarks.—This family agrees with the Protasteridee in not 
having the ambulacral ossicles of each segment placed opposite 
one another. It differs by having the ambulacral ossicles longer 
than wide, and never divided transversely by muscular depressions. 
The ambulacral ossicles are either bar-shaped or thickened to a 
subquadrate form. They are never boot-shaped. 
Genus 1. Panxopurura, Stiirtz, 1890 [16. p. 233]. 
Diagnosis.—Paleophiuride with the disc surrounded by rod- 
shaped marginal ossicles. The ambulacral ossicles are rods lying 
parallel to the arm. 
Distribution.—Lower Devonian, Bundenbach. 
Type species.—Paleophiura simplex, Stiirtz. 
Genus 2. SrurTzuRA, nov. gen. 
Diagnosis—Paleophiuride having thick, subquadrate, ambu- 
lacral ossicles and narrow adambulacral plates. The disc is fragile, 
and its plates are small and thin: it has no marginal plates. The 
mouth-frames are narrow and separate. 
Distribution.—Silurian, England and Australia. 
Type species.—Sturtzura brisingoides (Gregory), 1889 [5]. 
Remarks.—This genus differs from Palewophiura, as the ambu- 
lacral ossicles are thick and subquadrate, instead of being in the 
