lO 



ECHINOIDEA. I. 



are perfectly recognisable, and therefore his names ought to be restored to their riglits. The name of 

 P. triphylla of Muller, liowever, no doubt includes as well oijhicephalous pedicellariæ as triphyllous 

 ones. This name must then be kept for the small form the valves of which resemble clover-leaves, 

 while Valentin's name P. ophicephale is kept for the form described by him under this name. — 

 Haniann (184) uses the name <,Globiferen» especially of the pedicellariæ where the mucous glauds on 

 the stalk have been so highly developed, that the head has become rudimentary or is even quite 

 wanting. Thus they, as is also admitted by Hamann himself, are not a peculiar kind of organs, 

 but only transformed pedicellariæ; it may, perhaps, be as well to have a special name for these pedi- 

 cellariæ, but the name of «Globiferæ» cannot be restricted to them, as has also been observed by 

 Duncan (130). It is, in reality, contrary to all common practice not to use the names of Miiller. 

 The reason for keeping Valentin's names given by Geddes and Beddard (163): both on account 

 of their general acceptance and because they were the first names applied to pedicellariæ after the 

 determination of their real nature; Mitller's nomenclature refers to pedicellariæ as a genus of para- 

 sitic animals , is not sufficient for a disregarding of the common rules of priority. Accordingly the 

 names that ought to be used, are the following: 



Globiferous pedicellariæ — Pediccllaria globifcra Miiller 



Tridentate — 



Ophicephalous — 



Triphyllous — 



trideus — 



ophiocephala Valentin 

 triphylla Muller 



Pedic. gemmiforme Valentin, Perrier. 



P. armé Perrier (in the Cidarids). 



< Globiferen Hamann. 

 ( P. tridactyle Valentin etc. 

 \ P. inernie Perrier (in the Cidarids). 

 ( P. triphylla Miiller pro jjarte. 

 I P. buccale Valentin, Hamann. 



P. trifolié Perrier. 



To facilitate the understanding of the descriptions in the following, figures are annexed 

 showing a single valve of each of the four kinds of pedicellariæ together with the names used for 

 the separate parts. 



To be able to stud)' the pedicellariæ, especially the calcareous skeleton, which is of particular 

 importance for the classification, they must necessarily be treated carefuUy. On being boiled in 

 a not too strong solution of potash the separate pieces of the skeleton may easily be isolated, and no 

 very great technical skill is necessary to be able to make preparations in Canada balsam of these 

 pieces. (They cannot be kept in glycerine, as it resolves the lime). Accordingly I can in no way 

 subscribe to the opinion of Pomel that the pedicellariæ only with difficult\' can be used for the 

 classification, because «leur ténuité en rend l'étude peu pratique (324 p- 13). 



Also the spicules yield good systematic characters, even if they are not, in this respect, equal to 

 the jjedicellariæ. They only rarely yield specific characters, and are oftenest very similar in the sepa- 

 rate genera of the same family, but they may yield excellent family characters. They may be 

 of a simple C-.shape («bihamate >) — the most common form — or a little branched in both ends 

 yStrongyloccntrofus)^ or pointed in both ends, and with one branch or a couple of small branches in 

 the middle, cbiacerate (Parasalrnia, Anf/iocidaris); in Spli(rrccliini(s and especially in Toxopuciistcs and 



