IXIINlOIIll'-.A. II. 



79 



in the ambulacra! plate Y. b. r, but not in La. i. I may call attention to the fact that the abactinal plates 

 of the odd interambulacrum are alternating, not paired as in P. Jeffreysi, as correctly figured by Agas- 

 si/, and Loven. The pedicellariae are upon the whole well figured in the Challenger -Report, though 

 no mention is made of them in the text. The forms figured there are globiferous, ophicephalous and 

 tridentate. The globiferous pedicellariae (figured in PL XLV. Fig. 56 as a broad based, slender-pronged, 

 and hooked pedieellaria ■■) agree rather closely with those of /'. carinata. The ophicephalous pedicel- 

 lariae (figured in PI. XLII. Fig. 18, XLIII. Fig. 16 and XLV. Figs. 53— 54 as Clypeastroid-like pedi- 

 cellariae) differ from those of P. Jeffreysi in having more numerous teeth along the edge of the ter- 

 minal widening, and these teeth continue along the : dorsal side of the widening, whereas in Jeffreysi 

 they are only found along the inner side. This feature is well shown on PL XLV. 53. - ■ The pedi- 

 eellaria figured in PL XLIII. 17 is said to be a small Clypeastroid-like (ophicephalous) pedieellaria. 

 This must, evidently, be a mistake; the long neck shows that it is no ophicephalous pedieellaria, this 

 form of pedieellaria; being always devoid of a neck in the Irregular Echini. Probably it is a small 

 tridentate pedieellaria like that figured in PI. XLII. 20, only with the valves opened. The tridentate 

 pedicellariae occur in two forms; probably there will be found intermediate forms as in carinata, but 

 I have not found such. The smaller form has simply leafshaped, more or less elongate valves, with 

 the apophysis continuing into the edges, (figured in PL XLII. 19 — 20, XLIII. 15 and XLY. 59 as large- 

 headeds pedieellaria;); the end-tooth is only little prominent in the larger ones. The larger form 

 (PL XLII. 17, XLV. 57 — 58) has very slender, narrow valves, ending in a rather short hook and with 

 the edges serrate only near the point; this is a rather large form, the head reaching a length of ca. o'j mm . 

 Regarding Pourtalesia rosea A. Ag. it is stated in the « Challenger ■■ -Echinoidea (p. 140) that the 

 tuberculation of this species, and the shape of the test, must have been very similar to that of Pour- 

 talesia ceratopyga*. In the British Museum are preserved only the anal snout represented in PL XXII. a. 

 Figs. 3—5 and some very poor fragments connected with a genital organ; from these fragments alone 

 it is certainly impossible to judge of the shape of the test — it seems even not very likely that they 

 belong to one species. The figures given in the Challenger Ech. do not give a better proof of the 

 shape of the test; the apical area figured in PL XXII. a. Fig. 6 with the large thin plates, showing 

 distinct concentric striation, recalls much more the thin plated Cystechinus clypeatus than a species of 

 Pourtalesia . and it still more resembles the apical system of Sternopatagus as pointed out by de 

 Meijere (Op. cit. p. 163). (I have been unable to detect the apical system among the fragments pre- 

 served in the British Museum). I want to maintain that there is no proof in the description and figures 

 given in the Challenger -Echinoidea, and neither is such proof afforded by the fragments preserved 

 in the British Museum, that the apical system figured PL XXII. a Fig. 6 really belongs to the same 

 species as that to which the anal snout figured in the same plate Figs. 3 — 5 belongs, and I for im- 

 part think it probable that this apical system does not belong to any Pourtalesia at all, no other 

 species of this genus having a compact apical system. To be sure, Duncan states in his «Revisiou 

 (p. 282) that the apical system of P. miranda is compact like that of P. rosea, as can most distinctly 

 be seen on the PL XVIII. Fig. 9 of the Revision of Echini . This figure, however, only shows four 

 genital openings close together - - it does not show anything of plates, especially of the posterior 

 ocular plates. Until P. miranda has been rediscovered and carefully examined we may think it probable 



