lo the genus Cidaris proper. (The type specimen of the C. annulifera has also 

 been examined by myself (Ingolf-Echinoidea. p. 172)V That Cidaris Liitkeni de 

 Lorioi is only a synonym of Steph. bispinosa cannot be doubted; the type-specimen 

 I have likewise examined. As for Schleinitzia crenularis I must refer to my work 

 on the Ingolf-Echinoidea, p. 20, 178. 



For detailed description and figures reference must be made especially to 

 the works cited of de Loriol and Döderlein. A few features only need yet to be 

 mentioned. 



The ambulacral and interambulacral areas are figured in PI. II. Fig. 3, 17. Accor- 

 ding to Agassiz (Op. cit. p. 394) the scrobicular circles are „ill defined, running into one 

 another along the middle of the horizontal lines of contact". On the specimens 

 before me the scrobicular circles are well defined, with a complete circle of small 

 tubercles. Evidently some variation may occur in this respect (comp, the descrip- 

 tion of Cidaris Liitkeni). In the ambulacral areas there is a series of tubercles 

 inside the primary ones, placed opposite to or a little below the latter. On the 

 inner part of the ambulacral plates a few (mostly two) small miliary tubercles 

 are found. 



Agassiz (Op. cit. p. 393) describes the abactinal system of the genus Stepha- 

 nocidaris as being „thin, movable, resembling, in fact, far more the flexible anal 

 system of Echinidæ proper than the massive abactinal system of Cidaridæ", and this 

 is, indeed, the only character given as distinguishing the genus Stephanocidaris. I 

 am quite unable to see in the apical area of this species any such difference from 

 that of other Cidarids; as will be seen from the fig. 18 PI. II it has quite the usual 

 form, and it is not more flexible than the anal system of other Cidarids. In fact 

 it might well be supposed, as suggested by de Meijere, that the specimens of Agassiz 

 were not really referable to this species. Be that as it may, the species bispinosa 

 must remain the type of the genus Stephanocidaris, which is characterized not 

 by the apical system but by the structure of its pedicellariæ, as I have shown in 

 my work on the Ingolf-Echinoidea. It may be pointed out that the tubercles on 

 the outer edge of the genital and ocular plates and partly on the inner edge of the 

 formerare somewhat elongate, as remarked by de Lorioi. in his description of Cid. 

 Liitkeni, though not so regularly as figured there (Op. cit. PI. IV. Fig. 3). In the 

 specimen figured* here the madreporic plate has two genital pores, an interesting, 

 but not uncommon abnormality. 



In his C. Liitkeni de Lorioi, finds the upper radioles finely striated longi- 

 tudinally, while in the rest of them „la surface de la tige est couverte de granules 

 un peu épineux, disposés en séries longitudinales un peu irrégulières dont les inter- 

 valles, aussi larges (fu'elles mêmes, sont garnis de verrues extrêmement fines". In his 

 C. bispinosa he finds them all finely striated longitudinally. It is true that some of 

 the spines (the upper ones) may be longitudinally striated with very fine striæ. 

 Transverse sections of such spines, however, show that they have no outer layer, 



