1038 DR. J. W. GREGORY ON THE CLASSIFICATION _—[ Dec. 15, 
Genus 2. Furcastnr, Stiirtz, 1886 [15. p. 79]. 
Diagnosis.—Disc circular small. Arms short, narrow, slightly 
flexible, tapering gradually. Ambulacral ossicles of a long central 
body and two short wings, which are attached only to the anterior 
corner of the ossicle. 
Distribution.—Lower Devonian, Bundenbach. 
Type species.—Furcaster palcozoicus, Stirtz’. 
Remarks.—In Stiirtz’s description he refers to the existence in 
this genus of ventral arm-plates, and even figures them. His 
type specimens are now in the British Museum, but I cannot 
verify the existence of any ventral arm-plates. His type (B.M. 
FE 3805), for example, seems to me to show almost conclusively 
that an open furrow ran along the underside of the arm. 
Genus 3. Patasrroprcten, Stiirtz, 1886 [15. p. 88]. 
Diagnosis.—Dise circular, large (badly preserved in the speci- 
mens; probably originally soft and irregular). Arms thick, broad, 
and somewhat lanceolate in shape. Ambulacral ossicles narrow, 
the lateral wings resting on the whole body of the ossicle. 
Distribution. Lower Devonian, Bundenbach. 
Type species.—Palastropecten zitteh, Stiirtz, 1886 [15]. 
Aganaster, sp., Miller & Gurley [12. p. 57, pl. ix. figs. 10, 
11], seems to me to be allied to Lapworthura, and at least a 
member of the same family. It apparently has no ventral arm- 
plates, but an open furrow, and thus differs widely from Aganaster 
It is probably a new genus. 
Family 3. HoLUIDIDaA. 
Diagnosis.—Streptophiure with the ambulacral ossicles united 
to form vertebral ossicles. Ventral arm-plates present, but there 
are no buccal shields. (Dorsal arm-plates present only in the 
highest genus.) 
Remarks.—This family includes three Devonian genera, which 
differ from the previous families of this order by the presence of 
ventral arm-plates and by having vertebral ossicles, which arti- 
culate (?always) by simple rounded pits and processes. The 
family differs from living Streptophiure by the absence of buccal 
shields and the simplicity of the oral armature. 
Genus 1. Eonurpra, Stiirtz, 1886 [15. p. 89]. 
Diagnosis—Dise rather large; the interbrachial outlines are 
deeply concave. Each syngnath consists of pairs of mouth-frames 
and jaws; a jaw-plate is present. The vertebral ossicles are small 
and the union of the two lateral elements incomplete ; the lateral 
? The Protaster daoulasensis, Davy (Bull. Soc. géol. France, ser. 3, vol. xiv. 
pp. 182-187), is an ally of Furcaster, 
