KCHINOIDEA. II. 



Agassi /. compares 3, 5 and 5, 9, whereas the most characteristic of them, fig. 22, is not mentioned. 

 If Profesor Agassi-/ had compared the figure 3 with fig. 9, and fig. 5 with fig. 22, as is the only 

 natural way to compare them, he would probably have agreed with my placing these species in two 

 different genera. Since Professor Doderlein now agrees with me in referring these two species to two 

 different genera, I think there can scarcely be any more doubt of the correctness of that view. On 

 the other hand my genus Pctalocidaris. established for Goniocidaris ftorigera, seems, indeed, untenable, 

 as pointed out by Doderlein (p. 96). The remarks by Agassiz on this genus (p. 22) are singularly 

 unfortunate. All the figures to which reference is made there are of Tretocidaris. The diagnosis of the 

 genus (p. 28) and a comparison of the figure of a large globiferous pedicellaria (PI. X. 27) with that 

 of Goniocid. tubaria (PI. X. 20) would have shown that the genus was not based on the small opening 

 of the point of these pedicellarise but on the elongated form of the blade. 



The association of Dorocidaris bracteata A. Ag. with Stephanocid-aris bispinosa may be wrong, 

 but having no specimen of the former at my disposal I am unable to say anything definite; since 

 Professor Doderlein has now completely altered the position of Stcphanocidaris bispinosa by finding 

 its large globiferous pedicellarise, of the form without end-tooth typical of the genus Cidarites Lamarck 

 (Cidaris Klein in Part I of this work), the form taken by me to be the large globiferous pedicellaria; 

 being, in fact, the small form, it is probable that I have likewise only seen the small form of globiferous 

 pedicellaria; in Doroc. bracteata. But as long as we do not know the large globiferous pedicellariae of 

 this species it is impossible to say with certainty to which genus it belongs. The characteristic, that 

 the abactinal system of Stephanocidans bispinosa is somewhat more flexible than in other Cidarids, 

 does not seem to me so extremely important as Agassiz holds it, since he finds it ; so entirely unique 

 among the Cidaridce that there is no excuse for associating with it a species with the abactinal system 

 of the species of Dorocidaris* (p. 23). On comparing vertical sections of tests of Stephanocidaris bispinosa 

 and Dorocidaris papillata I find that not only the apical system but the whole test is distinctly thinner 

 in the former. Certainly, I cannot consider this difference a very important character. Professor Doder- 

 lein also evidently holds this character to be only of secondary importance, since he unites Cidaris 

 bacuiosa and verticillata with Stephanot. bispinosa in the same subgenus. (Op. cit. p. 101.) 



Professor Agassiz evidently finds it too meaningless to deserve a refutation, when on account 

 of a general resemblance I ventured to suppose that Dorocidaris panamensis had the same kind of 

 globiferous pedicellaria; as Cidaris affinis. If he had found it worth while examining these structures 

 he would have found that my suggestion was quite right ', and he would have avoided the erroneous 

 statement that this species is the Pacific representative of D. papillata?,. 



For my suggestion that Goniocidaris > canaliailata might be a Stere.ocidaris Professor Agassiz 

 can see no reason, especially since it is quite contrary to my principles to refer living species to 

 genera established for fossil species. To Mortensen affinities as usuajly recognized by most writers 

 on Echini have no interest and have no value when not based on the pedicellaria; (p. 32). The cases 

 where I do refer living species to genera based on fossil species seem to me to show that I also 



1 I have had occasion to examine specimens of this species, identified by Professor Agassiz himself, in the U. S. 

 National Museum. The only difference of some importance between the pedicellarise of this species and those of C. affinis is 

 that no limb of projecting rods is found on the stalk of the large globiferous pedicellarise at least not on the few I 

 have examined. They occur very sparingly; I have only found them in two of the nine specimens examined by me in the 

 U. S. National Museum. 



