174 



ECHINOIDEA. II. 



genera and limit them to the species really belonging together, as shown by the combined char- 

 acters of the test and the microscopical features of pedicellaria; and spicules. I therefore thought and 

 still think that I was justified in retaining for the first group included under the subgen. Psamm- 

 echinus in Agassiz & Desor's (Catalogue raisonne» the name Psammechimts, neglecting the prev- 

 ious authors' rather confused use of the name. It is true that the expression « point de fortes entailles 

 buccales -■> in the original diagnosis does not suit well with P. varicgatus, — when large specimens are 

 considered. But if we take specimens of medium size (and such were, I think, the specimens cited in 

 the said work) the diagnosis suits fairly well, the mouth-slits being really comparatively small. The 

 fact that Professor Doderlein has accepted the name Parcchinus also makes me confident that I 

 was right in taking varicgatus (Blainvillei) as the type of Psammechimts. In the other case it is right 

 that the name Anapcsus would have to be used for the latter genus; but it seems to me that, if 

 there is no necessity for reviving such a rather unfortunate name, it ought not to be done. And though 

 it is certainly no absolute claim that the first named species in a group has to retain the name of 

 this group in case of further subdivision (and, of course, in case that none of the species are designated 

 as the type) it seems to me a natural thing to do so, and in any case, the author who first charac- 

 terises the divisions of the old group is entitled to do so. 



On the genus Brissopsis Lambert has given a careful study (p. 104—8), the results of which, 

 at first, appear to differ very much from the results of my studies. In reality they do not differ so 

 much, only Lambert has, from want of sufficient material of the recent species, been led to a wrong 

 interpretation of ^Brissus lyrifcru and thereby induced to use the names incorrectly. As the true 

 «,Brissus lyrifer» Lambert takes the form described above as Brissopsis atlantica, the « elongated type 

 of Brissopsis lyrifcra* of Agassiz. The form described above as Br. alta, the (globular type of Br. 

 lyrifcra* of Agassiz, Lambert identifies with nBrissus pulvinafus-. including within this species also 

 the form from the Northern Seas, the true Brissopsis lyrifcra. These erroneous premises given (— and 

 from the study of literature alone it would perhaps scarcely be possible to get any other result — ), 

 the conclusion is quite right, that Brissopsis lyrifcra and pulvinafus must be sharply distinguished. If 

 the right names are put in, viz. Br. atlantica instead of Lambert's Br. lyrifcra and Br. lyrifcra and 

 alta instead of Lambert's Br. pulvinafus, 1 it will be seen that Lambert's and my opinion are thus 

 far quite in accordance as regards these forms. Lambert refers them to different subgenera, viz. the 

 true lyrifcra (his pulvinatics) to the subgenus Brissoma Pomel, the Br. atlantica (his Br. lyrifcra) to- 

 gether with Br. luzonica to the subgenus Klcinia Gray. The latter name, however, ought to be 

 regarded only as a synonym of Brissopsis. This name was first used for the fossil species Br. clegaus, 

 with its petals of the same form as in luzonica etc. Lambert maintains Brissopsis and Klcinia as 

 two subgenera, distinguished by the character that one has the subanal fasciole <en anneau simple > 



from the genus Echinus. The main character of the genus Parcchinus (Lambert's Psammechinus) is to be found in the 

 peculiar globiferous pedicellariae. But Lambert, the eminent specialist in fossil Echinoids, is not inclined to recognize the 

 microscopical characters, which cannot be used for the fossil forms. I think, however, that I am right in maintaining that 

 the recent species, which alone can be fully studied, must form the basis of our knowledge of the characters important for 

 classification. If microscopical structures like spicules and pedicellariae prove to be of the highest importance for distinguishing 

 the recent forms, we are certainly not entitled to ignore them on account of their not being preserved in the fossil forms. 

 We must, on the contrary, acknowledge that the fossil forms are thus far not preserved in a condition fit for complete study. 

 1 It is well worth emphasizing that in the European Seas only one form of Brissopsis occurs, viz. that with div- 

 ergent petals, so that there cannot be the slightest doubt of the interpretation of the ^Brissus lyrijer* of Forbes. 



