ECHINOIDEA. I. 



unpaired tooth at the point. The mouth is large, broad below, more narrow above; it reaches to the 

 very point. The edge is set with small teeth, the upper one on each side somewhat more distinct, 

 sometimes much larger than the others (PI. VIII. Fig. 26). These two uppermost teeth may be bent 

 towards each other and coalesced towards the point, so that a little opening appears on the upper 

 side of this apparently unpaired end-tooth, and when this is the case the resemblance to the pedicel- 

 larise of D, papillata is considerable; but here, however, is never found the rather long, closed part 

 below the end-tooth, which is found in D. papillata. The lower limit of the mouth generally forms a 

 fine, regular curve. In a couple of specimens the point of the large globiferous pedicellarise showed a 

 deviating, but very irregular construction, which was much more like that in D. papillata. As these 

 individuals otherwise agree exactly with the others, this deviation must be taken to be abnormal. It 

 is a very conspicuous peculiarity in the large globiferous pedicellarise of this species that the back- 

 side is quite clear without holes all over the outer part of the blade; in D. papillata the back-side is 

 highly perforated and of a very complicate construction to the very mouth. - - Length of the head 

 ca. i mm , the stalk often a little shorter. The structure of the stalk as in D. papillata. 



The small globiferous pedicellariae are upon the whole of the same construction as the large 

 ones (PI. VIII. Figs. 28, 30, 36); the uppermost pair of teeth may also here be coalesced at the points 

 (PI. VIII. Fig. 23). I have not been able to find tridentate pedicellarise in any of the specimens in hand. 



The spicules of the tube-feet (PI. XL Fig. 28) are very characteristic, and yield an excellent 

 mark by which this species may be distinguished from the other Atlantic Cidarids. They are small 

 fenestrated plates placed in two separated longitudinal series; they do not join on either side, such as 

 is the case in D. papillata and Cidaris a/finis. They are most developed on the tube feet below at 

 the peristome, in the upper ones they are more simple and more like the common Cidarid-spicules. 

 In quite small individuals they are often only much branched, not yet perforated plates. Upon the 

 whole they are comparatively smaller than in D. papillata; they are slightly arched corresponding to 

 the form of the foot, and are as usual situated transversely on the longitudinal axis of the foot. 



In the intestine, the genital organs, and the organs of Stewart numerous spicules are found; 

 those of the intestine have three rays, the others are larger, irregular plates (PI. XL Figs. 12, 16, 23). 

 The dental apparatus shows no marked peculiarities. The auricles are rather high and narrow; on 

 the ambulacral areas small and fine processes are found. (In D. papillata and C. a/finis are likewise 

 found rather well developed ambulacral processes. (Comp. Duncan 129). (PI. VI. Figs. 5 6.) 



In some of the specimens the lower part of the spines is slightly reddish; otherwise this species 

 appears to have no marked colour. The preserved specimens are brownish. 



c<Ingolf St. 9. (64 18' N. Lat. 27" o' W. L. 295 fathoms. Bottom temperature 6 2). 16 specimens. 



6 4)- 4 



5 7)- 2 



4 4)- 4 



) i 



8 )- 4 



5 i)- 2 



Further we have 5 specimens from the Denmark Strait (64 42' N. Lat., 27 43' W. L., 426 fathoms) 

 obtained in 1889 by Wand el. 



