ECHNIOIDEA. II. 



79 



in tlie ambulacral i^late V. b. i, but not in I. a. i. I mav call attention to the faet that the abactinal piates 

 of tlie odd interambulacnun aie alternating, not paired as in /'. /c;^>v'j',?/. as correctly figured by A g as- 

 si z and Loven. The pedicellariæ 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 pedicellariæ (figured in PI. XLV. Fig. 56 as a broad based, siender-pronged, 

 and hooked pedicellaria ) agree rather closely with those of /'. cari>iata. The ophicephalous pedicel- 

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

 cellariæ) differ from those of P. [effrcysi in having more nnmerous teeth along the edge of the ter- 

 minal widening, and these teeth continue along the .dorsal^ side of the widening, whereas in Jrffrfysi 

 they are onh- found aloug the inner side. This feature is well shown on PI. XLV. 53. — The pedi- 

 cellaria figured in PI. XLIII. 17 is said to be a «small Clypeastroid-like- (ophicephalous) pedicellaria. 

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

 form of pedicellariæ being alwa\-s devoid of a neck in the Irregular Echini. Probably it is a small 

 tridentate pedicellaria like that figured in PI. XLII. 20, only with tlie valves opened. The tridentate 

 pedicellariæ occur in two forms; probably there will be found intermediate forms as in can'i/aM, but 

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

 the apophysis continuing into the edges, (figiu'ed in PL XLII. 19 — 20, XLIII. 15 and XLV. 59 as large- 

 headed- pedicellariæ); the end-tooth is only little prominent in the larger one.s. 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. 07'"'". 

 Regarding ]^onrtalcsia 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 Poiir- 

 talcsia ccratopyga-. 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 ver}- 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 piates, showing 

 distinct concentric striation, recalls much more the thin piated Cysfrcluiiiis clypcatus than a species of 

 Poiirtalrsia , and it still more resembles the apical system of Stcrnopatagiis as pointed out by de 

 Meijere (Oi3. cit. p. 163). (I have been uuable to detect the apical s\'stem among the fragments pre- 

 served in the British Museum). I want to maiiitain 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 Aluseum, 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 m\' 

 part thiiik it probable that this apical system does not belong to any Poiirfalcxia at all, 110 other 

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

 (p. 282) that the apical system of P. niiranda is compact like that of P. rosra, as can most distinctl)' 

 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 plate.s, especially of the posterior 

 ocular piates. Lhitil /''. miruiidii has been redisco\'ered and carefully e.xainined we ma\' think it [)r()l)al)le 



