212 PEOCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



Davenport and a new, fairly large species from the Cedar Valley near Rock- 

 ford. In the latter the two primibrachs are separate — a point which proves 

 to be an exception in this rare North American genus. Arthracantha, which 

 is found in the Hamilton, Portage, and Chemung of the Lake Ontario region, 

 is represented by fragmentary remains from the Independence shale near 

 Brandon. 



The Flexibilia are rare. A new species assigned to Dactylocrinus is founded 

 on a well preserved specimen from the Lime Creek shale at Bird Hill. It is 

 close to D. concavus (Rowley) from the Craghead Creek shale near Fulton, 

 Missouri, but has a granulose surface. The only other flexible crinoid is 

 Taxocrinus interscapularis Hall from Buffalo. 



Two species of Inadunata, 8'ynbatliocrinus matutinus Hall and Deltacrinus 

 harrisi (Worthen), have been described from beds at Buffalo and Davenport 

 respectively. A new form of Decadocrinus from Vinton, preserving the crown, 

 and some imperfect specimens of Cyathocrinus and of a doubtful Lecanocrinus 

 from the Lime Creek shale conclude this order. 



The class Echinoidea contain very unique remains and they are abundant 

 in certain zones in the Lime Creek shale. Unfortunately, the plates and spines 

 of the tests are dissociated, but are still in such close proximity that little 

 error, it is felt, is made in referring the separate parts to their approximate 

 position in the test. Moreover, the various species have not been found com- 

 mingled, but at different horizons and localities. Three genera, two of them 

 new and the other hitherto unknown, from North America are recognized. 

 They belong to the family Archseocidaridse. Devonocidaris has small, remark- 

 ably thin, and fragile interabulacral plates, bearing a central tubercle and a 

 few secondary tubercles ; a scrobicule is fairly well defined and a basal terrace 

 is present. Spines long and acicular. Teeth, braches, and other parts of the 

 lantern well preserved. Xenocidaris, described by Schultze from the Devonian 

 of Germany, is represented by a considerable number of trumpet- or club- 

 shaped spines, whose slender shafts terminate distally in flat or concave apices 

 surrounded by a marginal coronet of blunt spinules. These spines are specific- 

 ally distinct from the Eifel species. The third genus is named Nortonechinus. 

 Its heavy interambulacral plates are highly imbricate, indicating that the test 

 had considerable flexibility. The primary spines are stout and they expand 

 distally, until over the greater part of the test they are rendered polygonal by 

 mutual contact; their apical faces are flat. These spines formed a protective 

 covering over the test much as to the expanded spines of Colohocentrotus 

 a trains Brandt of our modern seas. Ambulacral plates and the parts of the 

 lantern are also preserved. 



At 5.30 the Society adjourned for the day. In the evening the mem- 

 bers participated in the annual dinner with the Fellows of the Geological 

 Society of America. 



