420 



DB. J. W. GEEQORT OlST THE 



the height one half the length and not one-third ; moreover, the 

 granules on the ridges between tlie poriferous furrows are less 

 numerous. In these respects the fossil agrees more closely with. 

 C. imperialis, a Miocene species from Crete. Michelin's figures 

 do not show the side-view of the test, but in his description he 

 gives dimensions which show the proportions. 



The following table illustrates the relations of the Cretan and 

 Armenian specimens of C. imperialis and G. olisiponensis : — 



Height 



Length 



Width 



Ratio of height to length . . . , 

 „ „ width ... 



Number of granules on ridge 

 between interporiferous 

 furrows 



C. imperialis. 



Michelin's 

 type. 



75 mm. 

 175 „ 

 145 „ 



1:2-3 

 1:1-9 



Specimen 

 from Urmi. 



47 mm. 

 92 „ 



87 „ 



1 : 1-95 

 1 : 1-85 



3-4 



C. olisiponensis. 

 Type. 



40 mm. 

 127 „ 

 105 „ 



1 : 3-0 



1:2-6 



10 



These dimensions show that the specimen is far closer to 

 G. imperialis than to G. olisiponensis. As the elevation of the 

 test is not illustrated in Michelin's figures, that aspect is shown 

 on Plate 28. fig. 1. The petals in this specimen are unusually 

 fiat, and the test is very thick. 



2. Clypeaster Gttientheei, n. sp. (Plate 28. fig. 2.) 



Diagnosis. — Test pentagonal, with well-rounded angles. The 

 base is flat, with sharp, slightly sinuous ambitus. Upper surface 

 flattened. Anterior slope at an angle of 45°-50°, fairly regular ; 

 posterior slope steep to a posterior foot-like projection. Length 

 of test approximately equal to the width, and 3| times as great 

 as the height. Apical disc excentric posteriorly. 



Petals very tumid, broad and completely closed externally ; 

 the outer end is broad and well rounded. The petals are long, 

 and reach about three-fourths of the distance from apical area 

 to the ambitus. The anterior ambulacrum is longer than those 

 of the parietal series. 



Periproct large, circular, and close to the margin. 



Granules of interporiferous ridges about four on each ridge. 



