EUCLYPEASTRIDAE. 505 



EUCLYPEASTRIDAE. 



Family Euclypeastridae FFaeckel, 186G, Generelle Morphol. 



In the Monographie des Scutelles the first attempt was made by Professor 

 Agassiz to separate the Clypeastroids into natural groups, based upon their 

 internal structure. Desor subsequently adopted, in his Synopsis, the sub- 

 divisions suggested by Agassiz ; these subdivisions, as far as we have studied 

 them, appear natural, and have been adopted, with the exception that the 

 subfamily of Fibularina of Gray has been retained, and has been separated 

 from the Laganidae, with which they had been associated by Agassiz and 

 Desor. 



This family contains Echini, with simple supports connecting the upper and 

 lower floors, either as pillars, walls, needles, or radiating partitions, and of 

 which the test is covered by spines of a uniform structure, the mode of 

 formation of the internal supports forming the principal basis for the 

 distinction of subfamilies. 



FIBULARINA. 



Subfamily Fibularina Gray, 1855, Cat. Ree. Echini, (emend.) 



This subfamily contains small globular Echini, with rudimentary petals, 

 high teeth, and simple partitions radiating, extending from the periphery 

 towards the actinostoine. 



ECHINOCYAMUS. 



Echinocyamus Van Piiel., 1774, Brief. 

 (See Part II. p. 304.) 



Echinocyamus pusillus 



Spatagus pusillus Mull., 1776, Prod. Zool. Dan. 

 [Echinocyamus pusillus Gray, 1825, Ann. Phil., p. G. 

 (See Part II. p. 304.) 



PL XI'. f. 3; PI XIII. f. l-s. 



Norway ; Mediterranean ; Azores ; Florida. 



