ECHINODERMATA. 33 



Wurtemberg. It is found likewise in the Coral Rag of Besancon, in the Corallian stage 

 at Chatel-Censoir, and at Druyes, Yonne, in Ain, Lsere, and other departments of France. 

 On the Continent Cidaris coronata is therefore a characteristic Coral Rag urchin ; but it 

 has never yet been found in this or any other stage in England. 



The ambulacral areas in Cidaris Fowleri are slightly prominent and undulated ; they 

 are nearly uniform in width throughout, and are furnished with two marginal rows of 

 nearly equal-sized, close-set granules (PI. I, fig. 4 e), which become larger near the peris- 

 tome ; within these marginal pairs are two other rows of smaller granules, with other 

 microscopic granulations interspersed among them ; these inner rows gradually disappear 

 above and below, and the marginal rows then come into juxtaposition; the poriferous 

 zones form wide ribbon-like depressions, nearly equalhng in breadth that of the area 

 (PI. I, fig. 4 e) ; the pores are oblong, and the holes forming a pair are set widely apart, 

 with a thick septum^ equalling the long diameter of the pores, separating them from each 

 other. In the large specimens there are seventeen pairs of pores opposite each of the large 

 tubercular plates. 



The inter-ambulacral areas are formed of large plates, nearly as broad as they are long 

 (PI. Ij fig. 4 b), their lines of sutures being very distinct in young as well as in old 

 individuals ; each column consists of from six to eight tubercular plates, and each plate 

 externally has a large flat, nearly circular areola (PI. I, fig. 4 e), slightly furrowed towards its 

 outer border ; in the centre rises abruptly the mammillary boss, the summit of which is 

 sculptured with about fifteen deep crenulations ; from the interior of these rises a short 

 cylindrical stem, which terminates in a small hemispherical, deeply perforated, spinigerous 

 tubercle, the diameter of the tubercle slightly exceeding that of its stem ; the margins 

 of the areolas are bounded by a circle of fifteen scrobicular granules (fig. 4 e), which 

 are arranged with much regularity, each granule having a microscopic circlet of granulets 

 around its base ; the scrobicular circles on the upper half are more fully developed than 

 those on the lower half of the test ; from the equator upwards, each areola has its own 

 distinct scrobicular circle ; but from that line to the peristome, one scrobicular line of 

 granules separates two areolas above and below from each other ; the miliary zone is wide, 

 and is thickly covered with very small granules, which diminish in size from the scrobicular 

 circle to the median suture ; among the principal granules filling up this interspace are 

 others of still smaller size; the entire granulation does not observe much regularity, 

 although it follows lines which somewhat describe the tract of the median suture : the 

 space between the scrobicular circle and the poriferous zones is not so wide as that 

 between the scrobicular circle and the centro-sutural line ; this space is Hkewise filled up 

 by granulations of the same size and character as those which fill up the median miliary 

 zone. 



The mouth opening measures half the diameter of the test at the equator, and the 

 peristome has a pentagonal form. (PL I, fig. 4 a.) In two of the specimens before us, the 

 lantern is preserved, consisting of five strong pyramidal jaws, armed with conical teeth. 



5 



