Dec, 1920] 



Cystids and Blast oids 



71 



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plates supports one of the vertical radiating win.^^-like partitions sep- 

 arating the compartments sheltering the arms. Alternating with the 

 tops of the larger oblong plates is another series of plates, narrowing 

 rapidly upward and forming the lower third of 

 the narrowly contracted part of the tegmen. 

 At its narrowest part, the diameter of this con- 

 tracted portion of the tegmen is scarcely 3 mm. ; 

 the individual plates of this portion can not be 

 differentiated in the type specimen. The upper 

 third of the much elongated "hour-glass" por- 

 tion of the tegmen consists of plates narrowing 

 rapidly downward and producing a structure 

 similar to an elongate funnel. The number of 

 plates forming the circlet here can not be 

 determined; it seems to be 8 but may be 10. 

 The top of the funnel like portion of the teg- 

 men widens into a narrow platform, appar- 

 ently 18 mm. in width, forming the top of the 

 compartments sheltering the arms. About 

 halfway between the top of the calyx and the 

 platform at the top of the funnel-like portion 

 of the tegmen, the body of the crinoid enlarges 

 to a diameter of 25 mm. 



The anal tube rising above the platform of 

 the tegmen is about 15 m^m. wide at its base, 

 and tapers gradually to a width of 4 m_m. or 

 less. It is composed' of hexagonal plates which 

 are almost equilateral at the base but become 

 narrower and smaller farther upward. 



At a distance of 15 mm. from the base of 

 the calyx the column consists of columnals 

 3 mm. in height, intercalated between which 

 are columnals only 1 mm_. in height. Toward 

 the base of the. calyx, both sets of columnals 

 diminish in height. The general diameter of 

 the column is about 5 mm., but short vertical 

 wing-like processes extend outward from the 

 larger columnals and apparently also from the 

 smaller columnals. In case of the larger col- 

 umnals these wing-like processes slightly exceed 

 1 m_m_. in length. Apparently there are 5 of 

 them within the circimiference of each colvmmal. 



The plates of the anal tube are very thick, 

 those near the lower part of the tube varying 

 from 2 to 3 mm. in thickness. The surface of 

 these plates is coarsely and irregularly nodose, 

 especially centrally. From this it is assumed 

 that the plates of the calyx also probably were 



f^:: 



Figure 4. 

 Eucalyptocrinns probosci- 

 dialis Miller. Type speci- 

 men. An outline of a col- 



umnal is added in the lower 

 more or less protuberant centrally, and the comer of the figure. 



