192 



ECHINODERMATA— PELMATOZOA 



THYLUM IV 



usualUj limited to a definite mimber. Radiah in contact all around. Arms resting 

 in compartments formed hy partitions attached to the tegmen. Silurian and 

 Devonian. 



Eucalyptocrinus Goldf. {Hypanthocrinus Phill.) (Figs. 

 291, 292). Calyx with a deep concavity at the lower end, 

 the B forming the bottom, and the B the sides of an 

 inverted cup. Supplementary pieces of the calyx con- 

 sisting of 1 X 2 interbrachials, and one interdistichal ; the 

 latter of the same form as the interbrachials, and nearly 

 as large as the two upper ones combined. Tegmen 

 elongate, its upper part extended to form a tube. It is 

 j composed of five ranges of plates, of which the two 

 middle ones are the least regulär in their arrangement, 

 and the upper one closes the centre. Attached to the 

 outer walls of the tegmen, and extending to its top, are 

 ten partitions supported by the interbrachials and inter- 

 distichals, which form deep, vertical compartments for 

 the reception of two arms each. Arms twenty, biserial ; 

 composed of very narrow pieces. Column round. Sil- 

 urian ; Gotland, England (Wenlock Limestone), and 



A Single species occurs 

 in the Devonian of the Eifel. 



Callicrinus Ang. (Fig. 293). Calyx flask - shaped ; 

 concavity at the base deeper and wider than in the 

 preceding, sometimes involving not only the radials, but parts of the 



Fig. 291. 

 Eucalyptocrinus regu 

 laris (Hising.). Silurian, -»t i a • /^-r- 



Gotland. Crown with North Amcrica (Niagara Group), 



arms removed from one - — 



ray in order to sliow tlie 

 niches in whicli they 

 repose. 



Fig. 292. 



iri : ri r2 : iri 

 dist. dist. 



FAicalyptocrinus rosaceus (Goläf.). Devonian; Gerolstein, Eifel. ^/Perfect crown. B, Ciagrammatic longi- 

 tudinal section of the calyx (h, Basais ; ri, Radials ; r2, First costals ; y, Lower, and ö, upper piece of the wing- 

 like processes). C, Tegmen. D, Dorsal cup (ri, Radials ; r'-J, First costals ; (/■, Intcrnidials ; disL, Distichais ; 

 int. dist., Interbrachials; r^, Palmars) (after L. Schultze). 



costals as well. Partitions for the reception of the arms much shorter, ex- 

 tending to less than half the height of the arms. Otherwise similar to 



