Vol. 56.] 



AND CICEROCEINUS. 



20: 



Kg. 1. — Diagram showing 

 the arrangement of the 

 plates of the calyx of 

 Brahmacrinus ponderosus. 

 (xl-5.) 



the calyx, but the second distichal is not so intimately incorporated 



with the calyx as the first. 



The first pal mars are connected 

 with the calyx by small plates 

 which extend between them and 

 the ventral disc ; their articular 

 surface looks vertically upward and 

 exposes a central canal, from which 

 ridges and furrows extend radiately. 

 A single interradial, which is 

 in union with two radials below, 

 occurs in each interradius (fig. 1), 

 but in the anal interradius addi- 

 tional plates are present, one on the 

 right of the median interradial and 

 two on the left (fig. 2). These 

 additional plates are united with 

 the radials below ; and those at the 

 extremity of the series, on either 

 side, meet also the costals and first 

 distichals. The single interradial 

 of the other interradii is clearly 

 exposed in one instance only ; it 

 meets the costal and first distichal 

 in front and the costal behind, 

 being separated from the first 

 distichal on this side by a supple- 

 mentary intervening plate. 



[In this and the succeeding 



the letters have the following 

 meaning : — R=radial ; C = 



costal ; D x - 

 ~D„= second 



= first distichal ; 



distichal ; P = 

 palmar ; I.H = interradial ; 

 I.A=interambulacral.] 



Fig. 2. — Diagram showing the arrangement 

 of the plates in the anal interradius of 

 Brahmacrinus ponderosus. ( x 1'5.) 



The dorsal cup passes gradually into the ventral disc : if we 

 assign all the plates that lie below the ambitus (which runs 



through the first di- 

 stichal) to the dorsal 

 cup, then the plates 

 that remain to be 

 described must be re- 

 garded as ventral. 

 In the centre of the 

 disc stands a single 

 plate ; next to it on 

 one side are the re- 

 mains of the excentric 

 anal tube (broken off 

 at a height of 7 mm. 

 from the base) ; the 

 rest of its periphery is 

 bounded by six other 

 plates symmetrically 

 arranged, three on 

 each side of the antero- 



