108 



GEODIA MESOTRIAENA. 



from sixteen to twenty. The oxyasters attain a larger size in var. megana 

 than in the other two varieties. 



DIMENSIONS OF EUASTERS OF GEODIA MESOTRIAENA. 







Var. pachana 



Var. megana 



Var. microana 







number of rays 



6-15 



5-13 



6-14 







total diameter 



19-37 



22-54 



24.5-42 



1 



Large oxyasters 



diameter of cen- 

 trum /( 



2.5-8 



2-8 



2-7 







li^nO'i'n C\\ FQT7G It 



8-17 



11-28 



8-17 







basal thickness of 

 rays n 



1.5-2.7 



1-3.5 



1.3-4 







number of rays 



9-10 



8-15 



11-20 







total diameter /£ 



17 



17-20 



11-17.5 



2 



Small oxyasters 



diameter of cen- 

 trum /( 



1.5-2.5 



3.5-5 



3-5 







length of rays p. 



7-8 



&-6 



3.5-7 







basal thickness of 

 rays /t 



1-1.5 



1-3 



0.7-1 .5 







number of rays 



20-25 



15-21 



19-23 







total diameter 



20-30 



19-32 



26-27 



3 



Large oxysphaerasters 



diameter of cen- 

 trum /( 



3-5.5 



4.5-8.5 



5.5-10 







length of rays /i 



7.5-8 



7-12 



7-11 







basal thickness of 

 rays /i 



1-1.5 



1.6-3 



1 . 8-1 . 9 







number of rays 



11-20 



6-18 



8-17 







total diameter /i 



8.2-14.5 



6-14 



7.5-14 



4 



Small stroiigylosphacr- 

 asters 



diameter of cen- 

 trum /t 



2.5-5 



2-4 



2.5-6 







length of rays ^ 



2.2-5.5 



2-7 



2.5-6 







basal thickness of 

 rays /( 



1-1.8 



0.5-2.5 



0.8-2.1 



The large oxysphaerasters (Plate 24, figs. 5b, 7c, 8b) are 19-32 f.i in total 

 diameter and have a spherical centrum 3-10 /j. in diameter from which from fif- 



