104 SVEN LOVEN, ON THE EClllNOIDEA DESCRIBEI) BY L1NN.«US. 



on tlie costals above tlic pores and aroiind thein, and on thc 

 radials, prominent knobs and more or less twisted ridges, while 

 on the sides tbe striatiou divaricates as usual. The projecting- 

 nib of the gill-supports is there, and the eolour is the same 

 as in the Linnean types c and d. 



Along with these and some other Gninean specimens of 

 the true A. Lixuhx L. there are a few others from Säo Thomé 

 of a pecidiar aspect, Tab. -7, fig. H. While the specimen just 

 described presents a local maximum of luxuriancc in its epi- 

 stroma, these are remarkable for showing that feature near 

 its minimum. Xone of them are full-orrown. The lar o-est 

 among the denuded has a diameter of 30 mm. witli a height of 

 14 mm. or 0,46; another has respectively 21 mm. aiid 11 mm. 

 or 0,52. In both the smallness of the tubercles is conspicuous. 

 The larger of them has fourteen plates in the interradium ;"), 

 and of the five series of tubercles the second reaches to the 

 fourth plate from the calyx. the third to the fifth and sixth, 

 the fourth to the sixth and seventh, the fifth to the eio-hth. 

 Consequently. the disks of the interradia being partly bare, 

 there is an indication of a står. To this, however, there is 

 an approximation in the typical specimen c, fig. ö. It is in 

 both made apparent by the minuteness of the new-formed tu- 

 bercles, and it seems that the peculiar aspect of the specimens 

 from Säo Thomé depends merely on the development of the 

 tubercles beinw more retarded relatively to the o-roAvth of the 

 other parts of the skeleton. In accordance with this the epi- 

 stroma, whilc laterallv raised into the characteristic ridsre-like 

 granules overhanging the margins of the larger scrobicular 

 circles, is condensed on the disks and on the calyx into the 

 continuous, here rather thin and divaricatingly striated layer 

 always seen in halfgrown specimens. As in siich the ambu- 

 lacral areolse are rather narrow. The colouring is upon the 

 whole the same as in the old Linnean specimens, only much 

 fresher, the bluish tiut of the grey being more vivid and the 

 zones chesnut. The spines, equalling about half the diameter, 

 are bluish or reddish, ])ale at the base, and yellow-tipped. 

 The upper ones on the ambulacra are short and sub-cylindricaL 

 then all become aciculate and slender. The basal ones are 

 llattened with the terminal crustule whitish, short, tapering, 

 with a single, strong, rarely bifid, rib. I have no doubt the 

 spines of the Linnean originals were like these. The figure 



