MONOGRAPH OF THE EXISTING CBINOIDS. 271 



Florometra serratissima (figs. 774, p. 362). Each ambulacra! lappet contains 

 a slender rod, which is straight or slightly curved, roughened, rarely forked at the 

 ends, and of moderate length, reaching usually nearly or quite to the underlying 

 sacculus. 



There are no deposits in the tentacles. 



Florometra magellanica. Each ambulacral lappet contains a delicate straight 

 rod, short or of moderate length, slightly roughened at the ends. 



There are no spicules in the tentacles. 



Cyclometra clio. Each ambulacral lappet contains a slender, rather long rod, 

 which is slightty bent in the middle. 



There are no spicules in the tentacles. 



Sarametra triserwlis (fig. 801, p. 378). Each ambulacral lappet contains a 

 large and conspicuous fan-shaped plate, with five or six very long, slender spines 

 along the convex outer border. The lower pointed end of this fan is continued 

 downward in the form of a long, straight rod to the edge of the pinnulars. 



There are no deposits in the tentacles. 



Zenometra colwmnaris (fig. 800. p. 378). Each ambulacral lappet contains a 

 very large plate, which is elongate, more than twice as long as broad, slightly con- 

 stricted in the middle, with rounded ends ; the outer border is very wide meshed and 

 bears a number of long spines ; the inner end usually bears from two to four long 

 spines, which run to the border of the pinnular, but these may be reduced to one 

 stout spine. In the middle of this plate, lying nearer the distal than the proximal 

 border, is a large oval hole elongated in the same direction as the plate itself, which 

 may communicate with the exterior near its outer end. 



There are no deposits in the tentacles. 



Psathyrometra 'borealis. Each ambulacral lappet contains a long and very 

 narrow band-like plate abruptly bent in the middle, at the base tangent to the 

 distal side of the sacculus, terminating outwardly in from three to five long spines, 

 which are parallel to each other. 



There are no deposits in the tentacles. 



Psathyrometra fragilis. The deposits in the perisome of the pinnules resemble 

 those found in Ps. ~borealis. 



There are no deposits in the tentacles. 



Psathyrometra antarctica (fig. 765, p. 362). Each ambulacral lappet contains 

 a large, stout, and conspicuous smooth rod slightly bulbous and roughened at the 

 outer end which runs downward at an angle of about 60 to the border of the 

 pinnular, then abruptly turns proximally and runs along the edge of the pinnular 

 to the bent portion of the succeeding rod. 



There are no deposits in the tentacles. 



Psathyrometra gracillima. Each ambulacral lappet contains a long and 

 slender, almost straight rod which is roughened at each end, more especially the 

 outer. 



There are no deposits in the tentacles. 



Eumorphometra conclnna (fig. 806, p. 378). Each ambulacral lappet contains 

 a long, thick, and conspicuous rod, making an angle of nearly 60 with the border 



