Boone, Echinodermata, Cruises of "Eagle" and "Ara," 1921-28 125 



Material examined : Four specimens, collected in seine in Porto 

 Padre, Cuba, in 3 fms., 1928, by the "Am." 



Color: There is an excellent color plate of this species in Dr. 

 Mortensen's report on the Echinoidea of the Danish Ingolf Expedi- 

 tion, pi. 1, fig. 1. The test is a clear red, the spines are alternately 

 lighter and darker bands of brownish. 



Technical description: This species has been very thoroughly 

 described in comparison with Dorocidaris papillata (Leske) by Dr. 

 Mortensen in the above report. 



The test of C. affinis is turban-shaped, wider than high, very similar 

 to that of papillata, as it also is in the breadth of the ambulacral 

 and the interambulacral areas and the number of ambulacral plates 

 for each ambulacral area 10 to 12. The interambulacral plates of 

 affinis are more closely covered with tubercles; there are 13 to 16 

 on the edge of each areole and outside of these there is a circle of 

 tubercles opposite to those of the first series. Beyond this second 

 series are several more tubercles more or less circularly arranged and 

 except a narrow strip at the median line the entire plate is covered; 

 also on the lower part of the test it is covered by these tubercles. 

 There are no furrows in the edge of the plates. The ambulacral region 

 in affinis is more diagnostic, having the secondary tubercles in the 

 lower part of the plate so that they are placed opposite to the intervals 

 between the primary tubercles. On only the uppermost and lowermost 

 plates of the ambulacral area the secondary tubercles are wanting ; 

 in the median area inside the secondary series there are some still 

 smaller tubercles. The pore area in affinis is comparatively broader 

 than in papillata. 



The spines of affinis are one to one and a half times the diameter 

 of the test, regularly tapering, blunt-tipped. Each spine has about 

 eighteen longitudinal series of coarse serrations ; the fine thorns 

 between these do not coalesce, whereas in papillata they do, forming 

 a reticulation. The radioles around the mouth are short, blunt, flat- 

 tish, without dents in the margin. There is an ampulla at the base 

 of the small spines, particularly well developed at the base of the 

 small spines of the apical area. 



The pedicellariae of affinis are characteristic of the genus Cidaris. 

 On the three specimens taken at Porto Padre, Cuba, the tridentate 

 pedicellariae are very numerous all over the test. The large, globifer- 

 ous pedicellariae are much less abundant. 



