CLARK: THE CIDARIDAE. 169 



forms. His proposed subgenera of Cidaris are, Plegiocidaris, Para- 

 cidaris, Procidaris, Polycidaris, and Eucidaris. In 1884 Zittel proposed 

 Anaulocidaris for a fossil cidaroid, and in 1885 Doderlein used the name 

 Discocidaris for some recent Japanese species. In 1887 Doderlein pub- 

 lished a classification of the Cidaridae, including the fossil as well as the 

 recent forms. Of the 22 genera which he recognizes, 15 include only 

 fossil species. He reject^ Stephanocidaris altogether, and uses Desor's 

 name Leiocidaris for Phyllacanthus. For some inexplicable reason he 

 considers Porocidaris sharreri A. Ag. as a living representative of 

 Pomel's genus Pleurocidaris. To another of Pomel's genera, Stereo- 

 cidaris, he assigns three recent Japanese species which he describes. 

 He proposes four new genera of fossil cidaroids, but only gives names to 

 three : Mikrocidaris, Triadocidaris, and Miocidaris. In 1889 Duncan's 

 " Revision of the Genera ... of the Echinoidea " appeared, with a classi- 

 fication of the Cidaridae, which at first sight seems unique, but on exam- 

 ination proves to be novel only in the rank assigned to the different 

 groups. The writer divides the family into two sections, of which the 

 first contains four genera and one subgenus, and the second contains 

 two genera. For recent forms only the genus Cidaris, with a sub- 

 genus Goniocidaris, is allowed, but the heterogeneous nature of such a 

 genus is so far acknowledged that it is divided into seven " divisions," of 

 which five contain the recent species. These five " divisions " with the 

 subgenus Goniocidaris correspond in name and contents to the genera 

 maintained by A. Agassiz. In 1902 Lambert proposed for certain fossil 

 and recent Cidaridae previously referred to Stereocidaris, the name 

 Phalacrocidaris, and in 1903 he suggested for some fossil species allied 

 to Phyllacanthus, the name Aulacocidaris. 



In 1903 Mortensen entirely rearranged the recent species of the 

 family, uniting or separating them according to resemblances or differ- 

 ences in the large globiferous pedicellariae. In this w r ay he makes thir- 

 teen genera and a subgenus, and although he uses the names of the six 

 genera of A. Agassiz, the grouping of the species is wholly different from 

 that writer's. Mortensen's classification is as follows : — 



Dorocidaris A. Ag. (emend. ), 4 species. 

 Tretocidaris, g. n., 3 species. 

 Stephanocidaris A. Ag. (emend.), 3 species. 

 Scbizocidaris, g. n., 1 species. 

 Cidaris Klein (emend.), 8 species. 

 Chondrocidaris A. Ag., 1 species. 

 Acanthocidaris, g. n., 1 species. 



