1896.] OF THE PALjEOZOIO ophiuboidea. 1039 



wings are thin. The adambulacral plates are triangular and each 

 of them bears several spines. The pores for the podia occur at 

 the middle of the lateral margin of the ventral arm-shields. 



Distnhiitwn. — Lower Devonian, Bundenbach. 



Tyi^e species. — Eoluidia decJieni, Stiirtz, 1886. 



Genus 2. EospoNDYtus, nov. gen. 



Diagnosis. — Disc circular. Ainbulacral ossicles completely fused 

 into vertebral ossicles, each of which, however, is traversed by a 

 pore. The adambulacral ossicles ai-e somewhat pear-shaped. The 

 podial pores are at the posterior angles of the ventral arm-plates. 



Distribution. — Lower Devonian, Bundenbach. 



Type species. — Eospondylus primigenia (Stiirtz), 1886 [15. 

 p. 77]. 



Genus 3. Miospondylus, nov. gen. 



Diagnosis. — Disc circular. Ambulacral ossicles completely 

 united ; each half of the vertebral ossicle is boot-shaped. The 

 oral angles each consist of a pair of syngnaths without jaw-plate. 

 The ventral arm-plates are small, and are not notched by podial 

 pores. 



Distribution. — Lower Devonian, Bundenbach. 



Type species. — Miospondylus rlienanus (Stiirtz), 1893 [17. p. 29, 

 pi. i. figs. 1-3]. 



BemarJcs. — The two genera Eospondylus and Miospondylus are 

 both founded on species described by Stiirtz, and included by him 

 in Ophiura. It is impossible that they can remain in this genus, 

 and Stiirtz, no doubt, only placed them there provisionally. They 

 agree in family characters with Eoluidia, but diiler from it in the 

 structure of both the ambulacral and adambulacral plates. The 

 differences between them would certainly rank as of generic value 

 among recent Ophiurids. To leave tlie two species in Eoluidia 

 wolild only encourage the neglect of specific characters and a 

 looseness of description which has already greatly retarded the 

 study of the fossil Ophiurids. 



Genus 4. Aganastee, Miller & Gurley, 1890. 



Syn. Ophiopege, Bohm. 



This genus was proposed by its authors to include a species 

 described as Protaster gregarius by Worthen and Meek. It has 

 nothing to do with Protaster and is clearly a member of the 

 StreptophiursB. As far as its characters are known to me it must 

 be included among the Eoluidida;. It differs from the rest of this 

 family by Ihe presence of dorsal arm-plates. 



Without the opportunity for the examination of more specimens 

 than there are in the British Museum, I do not care to attempt a 

 new diagnosis. Improvements on the original dingnosis of Miller 

 and Gurley must be left to American palsEontologists. 



Peoc. Zool. Soo.— 1896, No. LXVII. 67 



