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BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



stellate, very slightly depressed or on a level with the general plane of the surface. 

 The small clusters of zocecial apertures (4 to 10 in each) occupying the angles 

 between the rays may be elevated a little above the level of the maculae, but as a 

 rule the entire surface may be said to be even. In a few cases, however, the maculae 



Fig. 121.— Constellaeia vaeia. a, tangential section, X20, cutting several eays of a macula; 

 b, veetical section, X20, passing theough a macula. Wassalem beds (D3), Uxnoem, Esthonla. 



themselves are higher than the spaces separating them. Zocecial apertures subcir- 

 cular, inclosed by a very thin rim, and varying considerably in size, though approxi- 

 mately equal on each fragment. Width of interspaces varying correspondingly, so 



Fig. 122.— Constellaeia vaeia. a, veetical section, X20, of a small example; 6, teansveese 

 section of the same specimen, X20. Jewe limestone (D1), Baeon Toll's estate, Esthonia. 



that about the same number of apertures occur in a given space in all specimens. 

 Ten or 11 occur in 3 mm. in the intermacular spaces, while the diameter of the 

 apertures varies between the extremes of 0.15 and 0.25 mm. 



The smooth, ramose zoarium and the well-marked stellate maculae 

 of Constellaria varia are so different from associated forms that no 

 confusion is likely. 



