ECHINOIDEA. I. 



There are 7 plates in the interambulacral areas. In the ambulacra! area there is a little tubercle 



rOoi 



alternately between each two primary tubercles gel, as in Porocidaris purpiirata. The colour of the 



L c) oJ 



test is redbrown, and therefore the white, naked furrow of the interambulacral areas is especially con- 

 spicuous. - Locality: The West Indies (no nearer information). Should this species perhaps be 

 Gray's Cidaris annulatal 



Tretocidaris spinosa n. sp. The globiferous pedicellariae have no such reticulation as those 

 of T. annulata, and differ from those of T. Bartletti by the sides forming an almost straight line from 

 the basal siirface to the opening. (PI. X, Figs. 10, n). The small globiferous pedicellariae as in the 

 two other species (PI. X, Fig. 16). On the stalk no distinct, freely projecting calcareous ridges are 

 seen, only a marked swelling. (It is, however, possible that the limb of the stalk is found on other 

 specimens; in the two other species it was not found either in all the large globiferous pedicellariae); 

 triclentate pedicellariae were not found. The spines closely grooved, rather finely thorned, widened at 

 the point, of the same length as the diameter of the test. The actinal spines smooth, not serrated, their 

 points not widened. The small spines are strongly redbrown. There is a naked median line in the 

 interambulacral area, but it is only little conspicuous. 9 plates in the interambulacral area; thus the 

 large spines are somewhat more numerous than commonly, which gives to the animal a very charac- 

 teristic appearance. The tubercles in the ambulacral areas as in T. annulata. Locality : St Helena (no 

 nearer information). 



<s.Dorocidarisi> bracteata Ag. The globiferous pedicellariae much lengthened and narrow, with a 

 powerful hook at the end, and a rather small, triangular opening a little below the point (PI. X, 

 Fig. 18); the small pedicellariae of the same structure, tridentate ones simple. This form of pedicel- 

 lariae is further found in <.<Phyllacanthus-!> annulifcra (Lamk.), PI. X, Fig. 17, and Stephanocidaris bispi- 

 nosa (Lamk.), and these species will have to be united into one genus, which must keep the name of 

 Stephanocidaris. 



'tDorocidarisT Reini Doderl. The globiferous pedicellariae are of a very peculiar structure; the 

 mouth is placed in the end of the blade, surrounded by well marked teeth on the margin which is bent 

 a little outward. Schnauzenahnlich vorragend Doderlein says of the blade in this peculiar form 

 of pedicellariae, and it really resembles a snoiit to some degree. On the stalk a limb of short thorns 

 is found. The small pedicellariae are of a quite different structure, a well developed end-tooth being 

 found here, and the large mouth situated below the point. This form of pedicellariae is found in a 

 series of species, viz. Cidaris affinis (PI. IX, Figs. 9, 22, 24) (which is in no way synonymous with Doro- 

 cidaris papillata, as has been commonly supposed), tribuloides, galapagcnsis and, I suppose, also in 

 Dnrocidaris panamensis Ag. ; at all events this species, to judge by the figure, would seem to be most 

 nearly related to Cidaris affinis and Rcini\ it is scarcely a Dorocidaris. The following species have 

 pedicellariae of the same structure, but are distinguished by having a limb of long, freely projecting 

 calcareous ridges on the stalk of the globiferous pedicellariae: Cidaris metularia, Thottarsii (according 

 to Doderlein (116 p. 19) Cidaris Thouarsii has only a short limb on the stalk; the specimens examined 

 by me have long limbs), vcrticillata and baculosa. Further has (according to the statement of Doder- 

 lein) Phyllacanthus impcrialis the same kind of pedicellarise (whether a limb is found on the stalk 



The Ingolf-Expedition. IV. i. -, 



