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shaped series can usually be distinguished, although much more 

 irregular than the former, and there are some half a dozen 

 plates between the second series and the inferomarginal 

 plates. The ventrolaterals are uniformly covered v^ith very fine 

 granules, and the individual plates are separated only by shallow 

 grooves. The larger plates bear several valvate pedicellariœ which 

 are considerably elongated transversely (PI. XIII, fig, 217). For 

 instance, on one of the larger plates of the V-shaped series in 

 contact with the adambulacral plates I counted as many as some 

 ten pedicellariao ; it must, however, be remarked that the counting 

 of the individual pedicellariae on such a plate is attended with 

 some difficulties, since several of the elongated pedicellariae show, 

 as on the marginal plates, constrictions, and there are all degrees 

 of coalescence, so that the separation into individual pedicellariae 

 is not always distinct (PI. XIII, fig. 216). The smaller plates in 

 contact with the inferomarginal series are mostly destitute of 

 pedicellariae. 



Ahactinal plaies. — The abactinal plates are rounded -polygonal 

 and in all my specimens they can be distinguished into two groups 

 with tolerable precision, viz. radial and interradial plates. The latter 

 are larger and there are usually 4-6 plates in each interradius, 

 which are larger than the remaining plates near the superomar- 

 ginal series, the whole forming a somewhat triangular group. The 

 radial plates are smaller than the larger interradial plates and 

 occupy the whole abactinal surface of the arms between the 

 marginals, and on reaching the disk they are continued on, with 

 diminishing breadth of the whole group, towards the centre, where 

 all meet together and form a group of central plates. In this 

 central group one can mostly, though not always, distinguish a 



