ECHINOIDEA. I. 



103 



2 — 4 teetli on eithei' side. The basal part has soniewhat projectiiig outer coruers. The ophicephalous 

 pedicellariæ are of tlie commoii form, the triph\llous oiies resenible tliose of Fxli. margaritaceus. — 

 Agassiz savs, but wrongly, that only tvvo kinds of pedicellariæ are foiind in this species, -oue small- 

 headed, long-stemmed, the other short-stemmed with a conical head >. He gives, however, no figures 

 of them. Unfortunately I can give no informations as to the peristome, as I forgot to examine it 

 dnring my stav at British Mnsenm. Neither can I tell whether the actinal primary spines are curved 

 at the point. Primary spines are fonnd on all the ambulacral piates; all the ocnlar piates are shnt 

 off from the periproct. The central plate little conspicnous. The spicules bihamate, nnmerons. 



Echiniis Nnimaycri Meissner is also to be classed with these species, but is, however, rather 

 sharply distinguished by se\eral characters. In the description by Meissner (285) only the apical area 

 is more thoroughly exaniined; as the t>pe specimen has been sent me for closer examination, I am 

 able to call attention to several other characteristic features of this species. A primary tnbercle is onh 

 fonnd in every other ambulacral plate. Unfortunately all the primary spines are broken, so that 

 nothiug can be said as to their length, or whether the actinal ones are curved at the point — what 

 is probable. The secondarj' spines are rather coarse, not fine, silky, as in the two preceding species; 

 tliey are, however, finely serrate. Three of the ocular piates reach to the periproct, as observed by 

 Meissner; no conspicnous central plate is fonnd. The apical area of the type specimen is, no doubt, 

 abnormal, two of the genital piates being coalesced, and the adjoining one uncommonly broad; by this 

 arrangement the two ocidar piates at these genital piates are situated opposite to the latter, and not, 

 as is elsewhere the case, opposite to the interspaces between them. (See the figure of Meissner. 

 Op. cit. p. 12). The buccal membrane contains numerous small fenestrated piates inside of the buccal 

 piates, outside of these it is almost naked, only with cpiite few, small fenestrated plate.s. Spines are 

 found on the buccal piates. The globiferous pedicellariæ (PI. XIX. Fig. 14) recall those of Ech. hor- 

 ridus very much, but the outer coruers of the basal part are somewhat more conspicuou.s, and the 

 edges of the blade are connected by cross-beams; there are i — i or 1-2 lateral teeth. The tridentate 

 pedicellariæ (PI. XX. Fig. 11) resemble those of Ech. margaritaceus^ as is also the case with the triphyl- 

 lous ones (PI. XX. Fig. 7); tlie ophicephalous ones of the commou form. The spicules bihamate, very 

 few; I have only seen a few in the buccal membrane, none in the tube feet. 



Echi)iits niagellaniciis Phil. To the descriptions of this species by Philippi and Agassiz the 

 following informations must be added. A primary tubercle is found on all the ambulacral piates; the 

 actinal primary spines are curved at the point, the secondary spines are coarse as in Ech. A^cuniayrri 

 and almost smooth. The buccal membrane is quite naked both inside and outside of the buccal piates, 

 and no spines seem to be found on these. The periproct is small, covered by a few, rather large piates, 

 without distinct central plate; generally one ocular plate reaches to the periproct, as observed b\- 

 Agassiz. The globiferous pedicellariæ (PI. XIX. Fig. 23) chiefiy as in Ech. margaritaceus^ with i — 2 

 teeth on either side. The tridentate pedicellariæ (PI. XIX. Fig.s. 11, 17), which are (always?) verv small, 

 o-5'°", are rather different from those of the other species; in the outer jjart where the valves join, the 

 edge is finely serrate, in the Iower part it is smooth, but rather thick; no net of meshes at the 

 bottom. The valves are apart for a ratlier long space, but the slit between them is quite narrow. 

 The ophicephalous and triphyllous pedicellariæ of the connnon form. The spicules bihamate, numerous. 



