MOls^OGEAPH OF THE EXISTING CRINOIDS. 



transverse (greater) diameter of the central canal. It is slightly constricted 

 between llie muscular fossa?. . , , 



The caNdtv on the ventral surface of the radial pentagon is hlled nearly to 

 the height of the distal edges of the muscular foss^ with a loose calcareous 

 flpnns;it showino" uo Central canal. 



' D ameter o^f radial pentagon at base, 3 mm.; height of articular face, 1. mm.; 

 width, at transverse ridge, 2 mm.; distance from center of rosette to middle^ o 

 lorsa outer edge of radial, 1.3 mm. ; distance from center of ventral face of radia 

 pentagon to middle of ventral edge of radial, 0.8 mm.; to apex of interradial 

 angle. 1.5 mm. 



COMATILIA IRIUOMETRIFOKMIS. 

 Figs. 13, 14. p. lo. 



The articular faces of the radials are entirely and widely ^JP-'^^^^J™^ 

 each other, just as in Neometra, by broad interradial processes formed by the 

 produced lateral edges of two adjacent radials. The outhne of each radial ace 

 as a vhol is approximately semicircular. The production of the lateral edge^ 

 of the radials has produced a corresponding distortion of the elernents of the 

 articulai faces, thes'e being laterally curved outward and somewhat elongated 



'""irdcfrsal ligament fossa is deep, and about two and one-half times as broad 

 as hi.iT. The ligament pit is very narrow, though nearly as wide as the trans- 



^^^i:tt:::^::iS^tament foss. are triangular, with their inner ap^es 

 on the level of the distal border of the central canal. The proxmial and distal 

 eS^^es mike approximatelv the same angle with the horizontal, and are nearly 

 it;" M; the outer edges! which are about two-thirds the length of the other 



'^\Te rrclffrrf^rm elongated triangles with their apices outward. Their 

 greatest height is equal to the distance from their lower borders to the transverse 

 ridffe- their inner edses are strongly convex. , i w iw 



A broad undifferentiated area incloses the central canal and extends latexa y 

 in tht form of a lon<r ande to the ends of the transverse ridge, its dista border 

 ol owin" nd being^delimited by. the proximal border of the mterarticular liga- 

 m nt os^: anteriorly (distally) this area is continued as a narrow intermus- 

 ™lar septum concave on the summit which rapidly diminishes m height being 

 replaced afer the proximal third of the muscular foss. by a narrow xntermus- 



'"''Thr^ntral surface of the radial pentagon, which is sharply stellate is 

 covered bv a somewhat concave loose calcareous deposit showing a ^"-^ 1 ee'iti..! 

 Sna The produced interradial angles, and a border equal ^^ ^^--"^f f.^"^^ 

 widih of these interradial processes about the distal edges of the radial faces, 

 are free from any secondary calcareous covering. 



