9 8 



ECHINOIDEA. I. 



not serrate, and that the apophysis does not widen to a cover-plate, contrary to the triphyllous pedi- 

 cellarise of the Echinothnrids. All four kinds of pedicellarise are certainly found in every species; but 

 of some species individuals may often be found, where globiferous or tridentate pedicellarise (sometimes 

 both forms) are quite wanting or very few in number (for instance Echinus Alexandri). This fact, 

 of course, is an unfortunate circumstance, but the value of the pedicellarise as systematic characters 

 are not otherwise lessened by it. 



If we now examine the genera and species referred to Triplechinida and Echinometrada 

 with special regard to the features described above, we shall get a view of their relations very different 

 from the views expressed in the above mentioned systems. 



The genus Echinus is notorious for its difficulty. A great many species have been described, 

 but most frequently the descriptions are insufficient, so that the species cannot be recognized by them. 

 One species, Ech. a cut us, is very varying, and has occasioned the establishing of a great many 

 « species •■•■, which nobody has been able to recognize with certainty, and by which the confusion has 

 only been increased. But even excellently characterized species, as for instance E. elegans, have often 

 been confounded with other species, what I have repeatedly been able to substantiate; what is hitherto 

 stated with regard to the distribution of the Echinus-species, must accordingly be used with great 

 caution. The reason of all these difficulties is almost exclusively to be found in the literature: an 

 exact examination of the animals themselves shows that the species upon the whole have rather 

 distinct characters. 



The following species are referred to the genus Echinus: miliar is Mull., microtuberculattts Blv., 

 angulosus (Leske), esculentus L., acnfus L,amk., norvegicus Dub. Kor., Flemingii Forb., microstoma Wyv. 

 Thorns., mclo Lamk., elegans Dub. Kor., gracilis Ag., IVal/isi Ag., lucidus Doderl., Robillardi Loriol, 

 darnleyensis Woods, magellanicus Phil., margaritaceus Lamk., horridus Ag., Alexandri Dan. Kor., albo- 

 cinctus Hutton, diadcma Studer, Neumaycri Meissner, multicolor Yoshiwara. A great many older names 

 are cited as synonyms to several of these species in Agassi z's « Revision of Echini ; a renewed exami- 

 nation of the type specimens of these «species* with especial regard to the pedicellarise might perhaps 

 give other results than those of Agassi z; but until such examinations have been made, we must build 

 on the results laid down in Rev. of Ech. . Of all the above mentioned species, with the exception 

 of Ech. multicolor, I have had occasion to examine authentic specimens, of Ech. horridus, Ncumaycri, 

 and Alexandri even the type specimens. The result is a considerable reduction of the number of 

 species in the genus Echinus, some of the mentioned species being dropped as synonyms, some prov- 

 ing to belong to other genera. 



As the type of the genus Echinus E. esculentus must be put down, the only one of the species 

 established by Linne. Of its characters the following ones must be mentioned here. Only every 

 other ambulacral plate carries a primary tubercle (in large specimens often 2 — 3 plates without primary 

 tubercle follow each other). All the ocular plates are shut off from the anal area. The buccal mem- 

 brane with numerous small and larger plates; spines on the buccal plates. The globiferous pedicellarise 

 without neck, the blade with a lateral tooth on either side, the edges connected across the inside. 

 The tridentate pedicellarise (PI. XVIII. Fig. 20) long, narrow, the edge set with numerous small teeth 



