Genera of Recent Clypeastroids, 597 



species in four genera — Echi no discus, Echinanlhns, Echino- 

 ci/amus, and " Genus 1/^ The fate of Echinanthus with its 

 constituent species has already been discussed. The deter- 

 mination of the type of Echinodiscus is by no means easy. 

 Lamarck ignored the genus, but Gray (1825, Ana. Phil, x.) 

 accepted it and only removed one of Leske^s fifteen species. 

 This one [E. laganum) he placed in a new genus, which he 

 called Lagana, a misprint (as shown by his quotation from 

 Klein) for Laganum *. By tautonomy Leske's species 

 becomes the type of the genus. Blainville (1830, Diet. Sci. 

 Nat, Ix.) used the name Echinodiscus, but as he did not 

 include even one of Leske^s fifteen species, his work can 

 hardly be said to help in the selection of a type. However, 

 he correctly placed Leske^s E. orbicularis in Gray's genus 

 Laganum. It was not vmtil Agassiz's monograph ' Des 

 Scute] les ' appeared in 1841 that Leske's heterogeneous 

 group was broken up. Of the thirteen species still in Echino- 

 discus, Leske, in 1841, we may dismiss 7'osaceus as unrecog- 

 nizable, and probably not an echinoid, while reticulatus is 

 clearly a Clypeaster. Of the eleven remaining species 

 Agassiz puts dentatus, octiesdigitatus, and deciesdigitatus in 

 his new genus Rotula ; for quinquiesperfuratus and sexies- 

 perjoratus he estal)lishes Mellita ; emarginatus and quater- 

 perforatus he included in his genus Eucope ; bisperforatus, 

 auritus, and inauritus he called Lobophora ; and subrotundus 

 lie places first in the Lamai'ckian genus Scutella. As this is 

 the only one of the species placed in Scutella by Lamarck, 

 which Agassiz also places in that genus, it is certainly 

 desirable, if not absolutely obligatory, to consider it the 

 type. It will be noticed that Agassiz makes four new 

 genera out of Leske's Echinodiscus, but ignores the name. 

 Of the four genera Lobophora is the last established, and 

 ought therefore to bear the old name ; and this is peculiarly 

 fortunate, for the name Lobophora is preoccupied and could 

 not therefore be used. A. Agassiz first called attention to 

 this in the ' Revision/ and restored Leske's name to the 

 genus. No type has ever been selected, and I therefore 

 choose E. bisperforatus, Leske, second variety, which 

 " longiora et angustiora linearia que foramina oifert." I 

 specify this variety because the other was named Lobophora 

 truncata by Agassiz (1841); and although Fourtau (1904, 



* The attempt to date this name from Meuschen, 1787, seems to me 

 most unfortunate. He is not a binomial writer, and I have no patience 

 with revising- the names of his catalogue. Many familiar Echinoid 

 names must take on a new meaning if his work is to he accepted. 



