MONOGRAPH OF THE EXISTING CBINOIDS. 



305 



Pterometra, Ptilometra (figs. 93, p. 153, and 361, p. 295) or Thalassometra (figs. 95, 

 p. 157, 96, p. 1.59, and 363, 364, p. 297). 



Though the idtiniate results of these two processes of elongation of the cirri, 



nil 11.1 111 1 1 n M I M-m \ 1 I I -r-[ 



^^CIIID 





FlQ. 3S5. 



Fig. JSfi. 



Figs. 3S4-386.— 384, Cirri from specimens of Leptomf.tra celtica taken in the Mdjcii. snowiNQ the various types (afteb 

 P. H. Carpenter). 3S5, Cirri from sPEaMESs or Leptometra celtica from off Cape Sacres, showino the various 

 tvpes (after p. H. Carpenter). 386, Cirri from specimens of LEPioMETR-t celtica from the Seixe Bank, suowtno 



THE VARIOUS TITES (AFTER P. H. CARPENTER). 



are very dilTcrcnt in their appearance, the firet giving elongate segments distallv, 

 rcsembUng those in the proximal jjortion, and the latter giving very short segments 

 distally, they are really the outcome of identical physiological or developmental 



