ECHINOIDEA. II. 



Agassiz compares 3, 5 and 5, 9, whereas the most characteristic of them. fig. 22. is m>t mentioned. 

 If Profesor Agassiz had compared the figure 3 with Kg. 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 otlur hand my genus Petalocidaris, established for Goniocidaris florigera, seems, indeed, untenable, 

 as pointed out by Doderlein (p. 961. The remarks by Agassiz on this genus ip. 221 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. 201 would have shown that the genus was not based on the small opening 

 of the point of these pedicellaria; but on the elongated form of the blade. 



The association of Dorocidaris iracteata A. Ag. with Stephanocidaris 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 eompletelv altered the position of Stephanocidaris bispinosa by finding 

 its large globiferous pedicellaria:, 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 

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

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

 the abactinal system of Stephanocidaris 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 Cidarida: that there is no excuse for associating with it a species with the abactinal system 

 of the species of Dorocidaris ip. 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 

 baculosa and vcrticiltata witli Stephanoc. bispinosa in the same subgenus. (Op. cit. p. 101.1 



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 pedicellariae as Cidaris affinis. If he had found it worth while examining these structures 

 he would have found that my suggestion was quite right 1 , and he would have avoided the erroneous 

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



For my suggestion that Goniocidaris canaliculate, might be a Stereocidaris 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 usually recognized by most writers 

 on Echini have no interest and have no value when not based on the pedicellariae ip. 321. The cases 

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



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

 National Museum. The only difference of some importance between the pedicellaria; of this species and those of C. ajfinis is 

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

 have examined. They occur very sparinglv: I have only found them in two of the nine specimens examined bv me in the 

 D. S. National Museum. 



