NOMINA NUDA. 457 



that a page 19 was separately printed and later issued. On inquiry at Albany and elsewhere, 

 I can find no trace or assurance of this extra page on which I presume these names appear. 

 Miller says that the descriptions are unrecognizable. The generic name HeterocidarK would 

 not hold as it was already given to a sea-urchin by Cotteau (Bull. Soc. G6ol. de France, 1800, 

 ser. 2, vol. 7, p. 378). The specimen of Pholidocidaris irregularis Meek and Worthen, shown 

 here on Plate 73, fig. 6, has pasted on the back a label, apparently in Hall's handwriting, 

 bearing the name Heterocidaris laevispina. Also a tablet bearing several plates of Pholido- 

 cidaris irregularis in the University of Michigan Collection, here figured on Plate 74, figs. 3-7, 

 bears in old manuscript the name Heterocidaris laevispina. It is therefore probable that 

 Hall's Heterocidaris laevispina is the same as Meek and Worthen's Pholidocidaris irregularig, 

 but, as it was inadequately described and the paper is unavailable, it is undesirable to 

 resuscitate the name. 



Messrs. Lambert and Thiery (1910, p. 124) erroneously refer Heterocidaris keokuk Hall 

 to Archaeocidaris keokuk Hall (this memoir, p. 267), but in their citation of page and Plate 

 they refer to the true Archaeocidaris keokuk Hall, which is published in the Report on the 

 Geological Survey of the State of Iowa, 1858, Vol. 1, Part 2, p. 699, Plate 26, figs. 2a, 2b. (By 

 clerical error Lambert and Thie"ry's bibliographical reference "956" is to Meek and Worthen, 

 and not to Hall's work, which in their bibliography is no. " 635.") 



Lepidocentrus desori Dollo and Buisseret, 1888, p. 959. 

 No description of this species has been published. 



Lepidocentrus duponti Dollo and Buisseret, 1888, p. 959. 

 No description of this species has been published. 



Lepidocentrus gaudryi Dollo and Buisseret, 1888, p. 959. 

 No description of this species has been published. 



Melonites youngi Young, 1878, p. 225. 

 Mehnechinus youngi Smith, 1901, p. 509. 



Young gives no description of this species of Melonites, but states that plates wen- first 

 found in Craigenglen (Scotland) and later in other localities. Young attributed th spec* 

 Keeping, but I cannot find that Keeping ever published it. Keeping (1876, p. 399) says that 

 Mr. J. Young had mentioned to'him traces of Melonites in the Glasgow shales. Smith nivc- 

 as localities for this species, Beith, Dobry, Muirkirk (Scotland), and says abundant but local. 



Palaechinus agassizi Dollo and Buisseret, 1888, p. 959. 

 No description of this species has been published. 



