256 



ECHINODERMA TA. 



[hvb. IOC 



Fia. 342.— Hybocy- 

 stites problematicus. 



Hybocystites, Wetherby. 1880, Jour. Cin. 

 Soc. Nat. Hist., vol. 3, p. 150. [Ety. 

 hubos, humpbacked ; kustis, bladder.] 

 Calyx like Hybocrinus, and order of 

 arrangement of the 

 two series of plates 

 is the same, but dis- 

 tinguished by hav- 

 ing three arm-like 

 projections, and two 

 or more recumbent 

 arms with ambula- 

 cral opening central ; 

 from the peristome, 

 the five ambulacra 

 diverge ; three are 

 directed to the arm- 

 like projections, and 

 are supposed to pass 

 over the top of them and extend down- 

 ward upon the exterior; valvular open- 

 ing between the upper azygous plate 

 and the mouth. Type H. problematicus. 

 problematicus, Wetherby, 1880, Jour. 

 Cin. Soc. Nat. Hist., vol.3, p. 150, Tren- 

 ton Gr. 

 Hydreionocrinus, DeKoninck, 1858, Bull. 

 Acad. Royale Belgique, vol. 8, pt. 2, p. 

 13. [Ety. hydreion, water-bucket ; kri- 

 non, lily.] Calyx short, rounded be- 

 low ; basals 5 ; subradials 5 ; radials 

 1x5; brachials 1x4 f 2x1; arms as in 

 Zeacrinus, and pinnules short; distin- 

 guished from Zeacrinus by the ventral 

 sac, which extends beyond the arms 

 and covers them like a roof; the upper 

 plates are convex or spinous ; respira- 

 tory pores in the sutures of the cylin- 

 drical part of the sac, which is covered, 

 by the arms. Type H. woodanus. 

 acanthophorus, Meek & Worthen, 1870, 

 (Zeacrinus acanthophorus,) Proc. Acad. 

 Nat. Sci. Phil., p. 28, and Geo. Sur. 111., 

 vol. 5, p. 563, Up. Coal Meas. 

 armiger, Meek & Worthen, 1870, (Zea- 

 crinus armiger,) Proc. Acad. Nat. Sci. 

 Phil., p. 27, and Geo. Sur. 111., vol. 5, 

 p. 547, Kaskaskia Gr. 

 depressus, Troost, as defined by Hall, 

 1858, (Zeacrinus depressus,) Geo. Sur. 

 Iowa, p. 546, Kaskaskia Gr. 

 discus, Meek & Worthen, 1860, (Zeacri- 

 nus discus,) Proc. Acad. Nat. Sci. Phil., 

 p. 39, and Geo. Sur. 111., vol. 2, p. 312, 

 Up. Coal Meas. 

 mucrospinus, McChesney, 1859, (Zeacri- 

 nus mucrospinus,) Desc. New Pal. 

 Foss., p. 10, and Trans. Chi. Acad. Sci., 

 p. 7, and Geo. Sur. 111., vol. 5, p. 563, 

 Coal Meas. 

 verrucosus, see Eupachycrinus verrucosus, 

 wetherbyi, Wachsmuth & Springer, 1886, 

 Revis. Palaeocrinoidea, pt. 3, p. 245, 

 Kaskaskia Gr. 

 Hypanthocrinites, Phillips, 1839, Murch. 

 Sil. Syst. [Ety. upo, under ; anthos, 

 flower ; krinon, lily.] 

 cselatus, see Eucalyptocrinus caelatus. 

 decorus, see Eucalyptocrinus decorus. 



Hysiricrinus, Hinde, 1885, Ann. and Mag. 

 Nat. Hist., p. 158, syn. for Arthracantha. 

 carpenteri, see Arthracantha carpenteri. 

 Ichthyocrini t 8, Conrad, 1842, Jour. Acad. 

 Nat. Sci. Phil., vol. 8. p. 279. [Ety. 

 ichthys, fish ; krinon, lily.] General 

 form, including incumbent arms, ovoid 

 or pear-shaped ; calyx cup-shaped ; ba- 

 sals 3; subradials 1 x5; primary radials 

 3 or 4 x 5, short and increasing, in 

 width, upward ; secondary and tertiary 

 radials similar in form to the primaries; 



arms 40 to 60 or more. Type 



I. laevis. 

 burlingtonensis, Hall, 1858, 



Geo. Sur. Iowa, p. v>7, l'.ur- 



lington Gr. 

 clintonensis, Hall, 18.*,!', Pal. N. 



V.. vol.2, p. 181, Clinton Gr. 

 corbis, Winchell & Many. 1866, 



Mem. Bost. Soc Nat. Hist., 



vol. 1, p. 89, and Jour. Cin. 

 Soc. Nat. Hist., vol. 4, p. 175, Ni- 

 agara Gr. 

 1 .'• v i s, Con- 

 rad, 1842, 

 Jour. Lead. 

 Nat. 8 c i., 

 vol. 8, p. 

 279, and 

 Pal. N. V., 

 vol. 2, p. 

 196, Ni- 

 agaraGr. 

 nohi lis. 

 War h- 

 gmiilh & 

 Sp r i d ger, 

 1878. Proc. 

 Acad. Nat. 

 Sci., p. 264, 

 Upper Bur- 

 lington and 

 K e o k u k 



Q r FiO. :U4— Ichtliync rimis I;. •vis. 



subangularis, Hall, 1863, Trans. Alb. Inst., 



vol. 4, p. 207, and 11th Rep. Geo. Ind., 



p. 268, Niagara < > r. 

 tiariformis, Troost, as defined by Hall, 



1858, (Cyathocrinus tiariformis,) Geo. 



Sur. Iowa, p. 558, Subcarboniferous. 

 Icosidactylocriniies. Not defined. 

 Iocrinus, Hall, 1866,, Advance sheets, 24th 



Rep. N. Y. St. Mus. Nat. Hist., p. 212. 



[Ety. to, in triumph ; krinon, lily.] 

 Calyx pentag- 

 onal, pyra- 

 midal sides 

 deeply eon- 

 cave ; basals 

 5, indented 

 downthemid- 

 dle ; radials 

 3 to <i x 5; 

 arms long, 

 frequently bi- 

 no pinnules; 

 extending be- 

 yond the arms, subcylindrieal longi- 



Fig. 345.— Iocrinus. Diagram; 

 6, basals ; r, radials ; n, azy- 

 gous plate; t, plates of 

 tube. 



furcating, but bearing 

 ventral sac very long, 



