Plate 30 



Smifti7ia ordinata (MacGillivray) 



Figure A: Very young zoid with four oral spines, lyrula, cardelle, and an incomplete 

 peristome. The spine bases extend into the calcifying peristomial band at this still-trans- 

 parent wall stage. Peristome incomplete proximally, lacking avicularium. Triangular 

 ledge against which the avicularium would have rested is in front of the lyrula. Drawn to 

 the 0.1 mm. scale at upper left. 



Figure B: Another young zoid but with three spines, lyrula, cardelle, and frontally 

 incomplete peristome. Avicularial chamber develops in shaded frontal area under the 

 incurved triangular peak. Drawn to the 0.2 mm. scale at upper right. 



Figure C: Another young zoid, with four spines and oral avicularium. The latter leans 

 against the triangular oral process shown in preceding figures. Same scale as figure B. 



Note: The material figured on this plate is from Station 226. 





