98 



FANAMIC DEEP SEA ECHINI. 



still showing the cellular structure of the outer part of the circle. The 

 miliaries and secondaries also show this cellular structure. (PI. 46, 

 figs. 5-7). 



I have given a number of figures (Pis. 44 ; 45, figs. 1-6) showing 

 the first formed auricular knobs (PL 45, fig. /), Fig. 136, still well sepa- 



43 mm. 



Fig. 137. 



Figs. 136-138. Phobmosoma hisi-idum. 



rated, with two ambulacral plates passed over onto the actinal system ; 

 next a somewhat older stage (PI. 45, fig. £'), in which the arch of the 

 auricles has become closer!, Figs. 137, 138, with five ambulacral plates 

 beyond the "auricles ; and still older stages (PI. 45, figs. 3-5) showing the 

 flow of the ambulacral plates, Figs. 139, 140, under the arch of the auricle, 



69 mm. 



Fig. 139. Phobmosoma iiispidum. 



137 mm. 



Fig. 140. Phormosoma hispidum. 



by the breaking up of the ambulacral plates into a median and exterior 

 part, the median carrying the pores beyond the auricle ; the outer part 

 left behind is crowded against the base of the auricles (Pis. 44, fig. 3; 

 45, figs. 5, 6). The suture of one of these plates can be seen at the base 



