LARVIFORM CRIXOIDS 



17 



varieties the collection contains several other forms most of which are smaller 

 than the figured varieties so that it is not certain that they are mature in- 

 dividuals and for that reason they are. not considered here. 



Kallimorphocrinus astrus typicus J. M. Weller, n. var. 

 Plate I, figs. 2a-c 



Description. — The height of the holotype is 1.07 mm. and its maximum 

 width is somewhat greater. Its horizontal outline is decidedly star shaped 

 with rounded corners separated by broadly concave sides. The radials form 

 about three-fourths, the underlying basal disc one-twelfth, and the crowning 

 orals about one-sixth of the total height. Some specimens possess a thin 

 stem joint firmly attached to the basal plates. 



The basals are firmly anchylosed into a low basal disc which slopes 

 regularly upward and outward to the suture which separates it from the 

 radials. It is pentagonal in outline and its upper and outer edge is beveled 

 for the reception of the radials. The circular stem facet occupies the whole 



O0O06 



Fig. -1 



Plan of the calyx of Kallimorphocrinus 

 astrus 



lower surface of the basal disc, is slightly concave, and is pierced by a single 

 small central opening. 



The radials are of similar size and form, subrectangular in outline but 

 somewhat wider above than below. Their height is about twice their mean 

 width. At their bases the radials are evenly convex but almost immediatelv 

 a rounded central keel is developed which becomes more prominent upward 

 owing to a widening of its flat lateral slopes. This angulation culminates 

 above in a prominent rounded knob the top of which bears the articular facet 

 for the arm. The upper corners of the radials are rather strongly beveled 

 and rounded, producing between the radials broad concave depressions in 

 which the orals rest. 



The articular facets of the radials are much smaller than in K. pocilhis. 

 In few specimens are the details of this structure recognizably preserved 

 but some specimens show a concave depression in the center of which lies the 



