' lAUK] CIDAKIS — DISCOIDEA HOLECTYrUS. 93 



( Ijipeasler ueomelricus Morton, 1834. Synop. Orgau. Remains, Cretacoou.s, p. 70, PI. 10, 



"Fi-.IO. 

 I'llijurus gcomdriciis Agassiz <aud Desor, 1847. Cat. rais., p. 141. 

 Pygnrus geomctrUnx d'Orbigny, 1847. Procliomo, vol. 2, p. 270. 

 Clypeaster geometricus Rronu, 1848. Iiulox Pal. vol. 1, p. ,312. 

 riigitrus qeomdricus d'Orbigiiy, 1853-'()0. Pal<5ont. fraufaise, vol. 6, p. 313, PI. 920, 



Fig. 4. 

 rggurus gcomctricus Dosor, 1858. Synop. des Echinidcs fossiles, p. 313. 

 Cli/peasicr gcomctrivus Gabb, 1859. Cat. Invert. Fossils, Cretaceous, p. 18. 

 Fygurus (?) geometncus Clark, 1891. Johns Hopkins University Circulars, No. 87, p. 77. 



The type of this si>ocics was examined l)y the writer, but its state of 

 preservation (that of a poor cast) is such that its generic relations can- 

 not be with certainty deternuned. Until further material is obtained 

 it seems best to defer its rei;ognition. 



Although originally desciibed by Morton as a Clypeaster, it has been 

 referred to the genus Pygurus by Agassiz, d'Orbigny, and Desor. The 

 single specimen was obtained from the lower marl bed (upper Creta- 

 ceous) of the Delaware and Chesapeake canal. 



CiDAKIS NAHALAKENSIS de Loriol. 



Cidaris nahalakensis de Loriol, 1887. Kecueil Zoologi(|ue Suisse, tome 4, jjp, 388, 389, 

 PI. 17, Figs. 3-4. 



The present species is based by P. de Loriol upon fragment of spines 

 obtained from the Rotten limestone of the upper Cretaceous of Nahalak, 

 Kemper county, Mississii)pi. The acceptance of the species is reserved 

 until fuller material has been obtained. Similar spines have been 

 recognized by the writer from other localities, but whether they repre- 

 sent an independent species or one hitherto described is not yet 

 clear. 



DiSCOIDEA OCCIDENTALE Gabb. 



Discoidea occidentale Gabb, 18(50. PLiladelijhia Acad. Nat. Sci. Jour., new ser., vol. 4. 



p. 398, PI. 68, Figs. 42-14. 



Discoidea occidentale Gabb, 187(5. Pliiladelphia Acad. Nat. Sci. Proc, vol. 28, p. 323. 



Discoidea occidentale Clark, 1891. Johns Hopkins University Circulars, No. 87, jj. 77, 



When tirst described in 18(30 Gabb referred this form to the Cretace- 

 ous of Oregon, but later, in 1870, thought he might have been mistaken 

 in the locality and mentioned Peru as its i)robable origin. In view of 

 this doubt it is omitted from the list of species. 



? HoLECTYPUS SIMPLEX Shumard. 



? HolecliipuH simplex Shumard (description unknown). 



Bulcclypus simplex Meek, 18(54. Smith Misc. Coll., vol. 7 (177), p. 2. 



? Holecljjpus simplex Clark, 1891. Johns Hoi)kins University Circulars, No. 87, p. 77. 



Meek includes 7/o?6!c^///>ws Himplex Shumard amotig his Ust of American 

 Cretaceous Echi nodermata and gives Texas as the locality. As a careful 

 search of the literature and extended correspondence with those familiar 

 with Sliumard's writhigs fail to elicit any information upon this jioint, 

 the writer is of the opinion that the reference to this species by Meek 

 is a mistake. No such species was probably ever described. 



