REPORT ON THE CRINOIDEA. 397 



to the Ecliinoidea aud partly to the Asteriadea, cannot by any means be applied to the 

 homologous parts in the Crinoid," i.e., to the basal plates. Loven,' however, objects to the 

 extension of the latter name to the so called genitals of Urchins and Starfishes, because 

 the position of their apical plates, " while basal in the Crinoidea, is culminating in the 

 Echinoidea and the Asteriadea, and consequently any appellation involving the notion of 

 a basal position must be avoided." ' There is undoubtedly some force in this objection ; 

 and I have long been endeavouring to find some general expression that would conveniently 

 describe the interradial plates in the apical system of all Echinoderms. Not having 

 succeeded in this quest, T have been obliged to fallback upon the word " basals." The 

 interradial position of these plates in the calyx of a Crinoid, as defined by Miiller,^ is 

 now universally recognised, and the use of the word is not likely therefore to lead to any 

 confusion respecting the position of the plates with regard to the general symmetry of 

 the Echinoderm type ; while it has the further advantage of avoiding the multiplication 

 of " terms already too numerous." As Loven objects to the use of " basals " for the 

 reasons given above, he seeks to avoid the introduction of new names by reviving the old 

 term " costals " of Miller. To this there could be no possible objection were it only 

 employed in the sense in which it was generally u-sed by Miller, but this is unfortunately 

 not the case. In seven out of the nine genera which were described by Miller as 

 having costal plates, this term was used for the radial plates of the calyx ; while it was 

 only in describing some species (not all) of Cyathocrinus that he employed the term costals, 

 for the interradial plates of the calyx or basals, and in the case of Marsujntes he gave this 

 name to the under-basals. Loven admits this inconsistency,* but adds that " it has 

 always been considered allowable to suggest the use in a strict sense of a term elsewhere 

 vaguely applied." This is of course quite true, but the term should surely be limited to 

 that sense in which it was most generally used by its author. This is not the case, 

 however, with Lovdn's revival of the term " costals," for he employs it to designate the 

 basal plates which were only called costals by Miller in four out of the many species 

 described by him ; while he applied this name to the radials in all the other cases in 

 which he used it at all, except in that of Marsupites. I cannot help feeling, therefore, 

 that this revival of a name which has been disused for half a century is somewhat 

 inexpedient, and is likely to lead to a confusion between the radial and interradial 

 plates of the apical system which it is very desirable to avoid. Every one knows that the 

 iuteiTadial abactinal plates of an Urchin or Starfish are not situated at the base of its 

 body as they are in a Crinoid ; and this reservation being made I do not see that there 

 can be any objection to calling them basal plates. This would avoid all possibility of 

 any confusion with respect to their position as regards the general symmetry of the 



1 On Pourtalesia, he. cit, p. 63. 



2 It may lie noted with respect to tLis point thatwlien Loven inverts an Urchin for a lietter comparison of its calyx 

 ■n-ith that of a Crinoid, his " costal " plates (the genitals) really do become " basal " in position (see p. 414). 



3 Bau des Pentacrinus, loc. cit, p. 25. ' * On Pourtalesia, he. cit., pp. 63, 64. 



