42 



ring of twelve considerably larger plates, which, with their lower 

 sloping sides, are placed between the triangular pieces, the point of 

 the angle touching the basal disk. Ten of these plates are hexago- 

 nal, two heptagonal, the former angular at the outer side, the other 

 two truncate. One of the latter is directed anteriorly, and supports 

 upon its upper truncate side the first radial of that side, the other 

 posteriorly, and is succeeded by a row of special anal plates, which 

 will be described presently. The plates are of nearly equal size, 

 higher than wide, connected laterally, and forming a continuous 

 ring, which in the specimen lies at the edge of the truncate, some- 

 what rounded portion of the calyx. 



The succeeding plates consist of six sections, and are radials, inter- 

 radials or anal plates. There are five rows of radials, separated 

 by four inter-radial series of from six to seven pieces. Two other 

 series of seven plates each, arranged like the former, occupy the 

 azygous side, and are separated, in place by radials, by a row of 

 four hexagonal special anal plates, which, with the exception that 

 the upper side of the upper plate is not excavated, have exactly the 

 form and size of the four radial plates at the anterior ray. This 

 ray has exceptionally four radials, hexagonal like the anals, which 

 with their truncate side are connected among each other, and with 

 the heptagonal piece of the second ring heretofore described. The 

 four lateral rays not only consist of but three plates, but these radials 

 have also a very different form , and are partly disconnected. The first 

 is hexagonal with upper and lower side angular, the second pentan- 

 gular, angular l)elow. Only in a single ray of the specimen do the 

 angles of the two plates touch each other, in the four others they are 

 separated by plates from different inter-radial areas which join here, 

 their suture forming a line between the angles of the two radials. 

 The first and second radials are all connected by a truncate side. 

 The third radials are one-half wider than high, hexagonal, contrary 

 to the first and second, which are a little higher. 



The inter-radials of the four lateral rays, toward the anterior side, 

 consist of seven plates in four series, '2, 2, 2, 1 ; at the anterior side 

 of only six pieces, 2, 1, 2, 1. The plates of the first series rest with 

 their lower sloping sides against two of the intercalated pieces — 

 those composing the second ring around the basals ; they are placed 

 with their lateral side against the sides of their fellows of the adjoin- 

 ing inter-radial area, except toward the anterior and posterior side, 

 where they abut, at the former against the first radial, at the latter 

 against one of the special anal plates. The plates of the succeed- 

 ing series rest with their outer sides within the angle between two 

 radials, with the other side against the adjohiing inter-radials. 

 The plates of the inter-radial areas are either hexagonal or pen- 

 tagonal, and their increase in size in an upward direction is even 

 greater in that same direction among the radials, the upper one 

 being fully three times larger than the two inter-radials of the first 

 series. The same is true with regard to the azygous side. 



The anal side is very wide, and is composed of a median row of 

 four hexagonal pieces, longitudinally arranged, and of a series of 



