36 • ECHINOIDEA. I. 



more closeh' covered with tul)ercles; there are ca. 15 011 the edtie of each areole, and ontside of these 

 there is a circle of tnbercles opposite to the intervals of those of the first circle. C)ut.side of these 

 again several tubercles are fonud, more or less circtilarly arrauged, so that the vvhole plate is covered, 

 witli the exception of a quite narrow stripe at the median line, — and on the lower part of the test 

 it is also covered by the tubercles. No furrows in the edge of the piates. In the depth of the 

 areoles there seems to be no distinct difference between the two forms. 



The ambulacral area is more pecnliar (PI. VI. Fig. 9); the secondary tubercles lie liere in the 

 lower edge of the plate, so that the>- are sitnated opposite to the intervals between the primary enes 

 (in D. papillata tliey, as described above, are placed in the niiddle of the ambulacral piates, opposite 

 to the primary tubercles). The whole form of the ambulacral piates is con.sequently .somewhat dif- 

 ferenl from that of /). pnf^Hlala. ()nl\- on the very uppermost and lowermost piates of the area the 

 secondary tubercles are wanting; in the middle part of the area inside the secondary series some 

 tubercles are found still a little smaller (the secondary tubercles are somewhat smaller than the primary 

 ones), i^laced opposite to the intervals between the secondary tubercles, and consequently opposite to 

 the ])rimary ones, not, however, very regularly. — The pore area is a little more than half the breadth 

 of the interjacent space, comparatively a little broader than in I), papillata, scarcely, howe\er, of au}- 

 great importance. 



The .spines i — 1'/2 time the diameter of the test (in I). papillata ca. 2— a'/j time.s); they are 

 evenly tapering, and end bluntly. About 18 longitudinal series of coarse serrations. Between these 

 longitudinal series fine, slightly brauched thorns are found, which do not coalesce and form a reticu- 

 lation as in /). papillata (transver.se section PI. XI, Fig. i). The radioles round the mouth are short, 

 l)lnnt, somewhat flat, without any dents in the edge, what they commonly have in 1). papillata. As 

 in tilis latter an <aiiipulla is found at the ba.se of the small .spines, especially well developed at those 

 of the apical area. There seems to be 110 difference of any imijortance in the form of the small spines 

 of the two species. 



The pedicellariæ are of the structure characteristic of the genus Cidaris. The large globiferous 

 pedicellariæ (PI. IX. Figs. 9, 22, 24): the mouth is .sitnated quite at the top of the blade which is round 

 and .somewhat bent inward; it is surrounded by a linib that is a Httle bent outward and provided with 

 rather large teetli the uuniber and size of which is ratlier irregular. The upper end of the mouth has 

 no limb nor any teetli; no end-tooth. The edge of the blade towards the point irregularly dentate. — 

 At the transition between the broad and the narrow part of the stalk a liiul) is found of freeh' pro- 

 jecting, .short calcareous ridges, prolongations of the rind-la)-er of the tliick part of the stalk (PI. IX. 

 F'ig. 12). Tilis limb is most developed on the large globiferous pedicellariæ, but may also be ratlier 

 distinct 011 the small pedicellariæ and the tridentate ones. The whole stalk is far more regularly 

 constructed than in D. papillata: liere the outer layer consists of smooth longitudinal ridges with small 

 knob-like swellings, in D. papillata it is an e.xtremely irregular, more or less spinous reticulation. — 

 Size: the head ca. 07""", the stalk ca. 2""", but especiall}- the latter is rather \-arying. 



The small globiferous pedicellariæ are of a quite different structure (PI. IX. Figs. 8, 11); they 

 have a distinct end-tooth, and the inoutli is large and sitnated a little below the point. The back-side 

 of the blade is almost without the common holes in the lime, onl\- the basal i)art is perforated as 



