MONOGRAPH OF THE EXISTING CRINOIDS. 265 



line drawn tangent to the outer borders of the latter; occasionally these rods are 

 forked at their outer ends ; frequently they are absent. 



There are no other deposits. 



Antedon bifida (fig. 1173, pi. 27, and pi. 50, fig. 1335). There are no calcareous 

 deposits in the perisome of the pinnules, nor in the tentacles. 



W. B. Carpenter has noticed that in the very young the perisome of the 

 arms and pinnules contains irregular branching spicules which form a sort of 

 incomplete reticulation for the support of the ambulacral lappets; these subse- 

 quently undergo complete resorption so that no trace of them is discoverable in 

 the adults. 



Antedon adriatica. There are no calcareous deposits in the perisome of the 

 pinnules, nor in the tentacles. 



Compsometra loveni. Each ambulacral lappet contains an extremely slender 

 hair-like short rod, usually slightly bent in the middle, which is tangent to the 

 proximal border of the sacculus. 



There are occasional spicules along the outer side of the tentacles. 



Compsometra incommoda. Each of the ambulacral lappets contains a minute 

 short straight rod. 



The tentacles contain a broad and conspicuous band of extremely fine spicules 

 along their outer side. 



Toxometra paupera (fig. 767, p. 362). Each ambulacral lappet contains a 

 conspicuous and unusually stout rod, roughened at both ends and bent in the middle 

 at an angle of about 120, which runs downward to the pinnulars tangent to the 

 distal side of the sacculus. 



There are no deposits in the tentacles. 



Dorometra parvicirra (fig. 789, p. 366). 



Eumetra chamberlaini. Each ambulacral lappet contains two slender cal- 

 careous rods ; the longer, slightly and evenly curved distally, just crosses the distal 

 edge of the sacculus ; the shorter is similar but only about half as long and corre- 

 spondingly more slender and is tangent to the proximal edge of the sacculus. 



There are no deposits in the tentacles. 



Iridometra adrestine. Each ambulacral lappet contains an excessively slender 

 very slightly curved rod, which in its lower portion is tangent to the proximal side 

 of the sacculus. 



There are no deposits in the tentacles. 



Iridometra melpomene,. Each lappet contains a slender curved rod, as in 

 /. adrestine. 



There are no deposits in the tentacles. 



Andrometra psyche. Each ambulacral lappet contains an excessively slender 

 slightly curved smooth calcareous rod which terminates just above, or just over 

 the outer border of, a sacculus. 



There are no deposits in the tentacles. 



TJiysanome.tr a tenettoides. From the border of the pinnulars into each of 

 the ambulacral lappets there runs a very narrow but very conspicuous calcareous 



