ECHINOIDEA. II. 5, 



liere; it is, however, evidently not very correctly drawn. I have seen nothing resembling the figiires 

 Pl. XLIII. 10 — 11; they probably represent only small specimens of this kind of tridentate pedicellariæ. 

 The second form (PI. X. Figs. i, 4, 24, 28, 29) is coarser and the form of the blade often somewhat irre- 

 gnlar; it has generally some very irregnlar meshwork. This kind of pedicellariæ is fonnd on the 

 actinal side, and especially on the peristome, even in the month they are qnite crowded, reaching 

 some way np the oesophagns; those fonnd here are generally more irregnlar than those on the out- 

 side of the test (PI. X. Figs. 28 — 29). — It is probably this second form of tridentate pedicellariæ which 

 is fignred in PI. XLIII. Fig. 12 of the Challenger -Ech. nnder the name of Clypeastroid-like pedi- 

 cellaria; the val ve represented in PI. XLV. F"ig. 35 as belonging to this form is certainlv that of an 

 ophicephalons pedicellaria, but it seems very unlikely th.at it can belong to this form; the figure 

 PI. XLIII. 12 does not seem so verv bad, as it wonld be in case the valve did realh- belone to it — 

 and on the otlier hånd, this coarse form of tridentate pedicellariæ is generally invested with a rather 

 thick, brown skin, so that by a superficial examination not much more is seen than the fignre cited 

 shows. — Tlie ophicephalons pedicellariæ are like those of /-*. Raf/ibttiii, the valves being low and 

 rather broad. The PI. XLV. Fig. 35 of the Challenger >-Ech. gives a rather good representation thereof. 

 The figures PI. XXXV. 17—18 mav perhaps also represent the ophicephalons pedicellariæ; they are 

 however, so crudely made that it is qnite nseless to specnlate on what they are meant to represent. 

 — The triphyllons pedicellariæ are like those of P. Rathbuni. The snpporting rods of the filaments of 

 the actinal tnbe-feet are like those of Urcchiims; spicules I have not seen. The spines evidently deserve 

 to be carefully studied ; nu* preparations however do not allow me to give more than a few remarks 

 thereon. The only (broken) primary spine I have seen does not agree with the figure and description 

 given by Agassiz, it is curved and finely imdulated along the longitudinal ridge.s. Clubsliaped spines 

 are fonnd at the actinostome as in Urrc/i. naresiamts. 



To the Urccliiiiidæ is fnrther referred the genus Calyiiiiic. The figures given in the Challenger 

 Report do not allow one to see the real structure of the anterior paired 

 interambulacra; finding that this was an iraportant character for the classi- 

 fication of the Meridosternata (viz. whether the second plate of these 

 interambulacra is single or double — Comp. below p. 85), I carefullv e.xamined 

 the fragments of the type specimens in the British Museum in tliis regard 

 and found that the first plate is in contact with two of the foUowing piates. 

 The unnsual size of the actinal ambulacral piates makes it a little diffi- 

 cult to see the real structure in the poor fragments preserved; but the 

 pores of the ambulacral piates are distinct and leave no doubt of the ^''S- 7- Part of the actmai sule 



of the test of Calymne relicta. 



morphological valne of the piates (Fig. 7). (The figure is made after a 



.sketch taken without camera and thus cannot claim to be qnite correct as regards the outline of tlie 



piates; but in the main features it is correct.) 



The apical system is certainly not very correctly given in the Fig. 2. PI. XXXIV of tlie 

 ;<Challenger3-Ech. The two anterior genital piates with the madreporiteseem to be confluent, not forming 

 two (or three) separate piates as in tliat figure. Of the two posterior genital pores seen in this figure 



