456 Miscellaneous. 



from others, with smooth scrohicule around which are numerous 

 small scrobicular tubercles in one or more circles ; these tubercles 

 are usually especially numerous on the adoral and adapical margins, 

 particularly the latter, where they form many close-serried rows. 



E. Mansterlanus is, according to Tornquist, the representative of 

 yet a third group, the characters of which he does not give. Does 

 he iiuow more of it than the radioles ? 



Tornquist has given no generic or subgencric names to the groups 

 defined by him, but Lambert (1900*, p. 42), while retaining for 

 the first group the name Echinocnnus (in accordance with the views 

 above expressed), has suggested the resuscitation of Archceocidaris 

 for the second group. This, of course, is quite inadmissible, as 

 already explained (p. 453). If a name be required, " Cldnro- 

 tropus " is ready to hand, with genotype G. Wortheni. But it is 

 really too early to make this division. Unfortunately so many 

 species have been based on radioles or on isolated interambulacral 

 plates that they cannot be referred with any security to either of 

 these groups. Perhaps we may be allowed to retain the word 

 " Archaeoeidaris " as a convenient appellation for such doubtful cases, 

 much as the word " Ammonites " still has its uses. 



The following statement summarizes the conclusions with regard 

 to the principal generic names mentioned in this study : — 



EoHiNocKiNus Agassiz, 1841. 



Genotype Ctdaris Urii Fleming. 



Syn. Archceocidaris, M'Coy, MS., 1844. 

 Falcmcidaris, Desor, 1846. 

 Archaocidaris, M'Coy, 1849. 



CiDAROTRoPus Pomel, 1883. 



Genotype Archceocidaris WortJieni Hall. 



Syn. Eocidaris Desor (pars), 18o7. 



Arcltccucidaris Lambert (nou M'Coy), 1900. 



Lepidocidaris Meek & Worthen, 18G0, em. Jackson, 1890. 

 Genotype Eocidaris'^ squamosa Meek & "Worthen, 1869. 



Of these genera, Echinocrimis and Lepidocidaris are well estab- 

 lished, but Gidarotropus rests, for the present at any rate, on an 

 insecure basis, and, if not accepted, must with its synonyms be added 

 to the list of synonyms of Ecliinocrinus. 



The choice of a name to replace Archoeocidaridse is therefore 

 limited to two. Echinocrinidoe, the natural successor, does not 

 suggest the systematic position of the Family so well as Lepido- 

 ciDARiD^, and I therefore propose to use the latter. 



* " Etude sur quelques Echin. de I'lufra-Lias &c.," Bull. Soc. Sci. 

 Youne, liii. l^r semestre, pt. '2. 



