ACTINOT'ODOUS HOLOTHCRIOIDEA. 



121 



two ambulacra arc locoguizablo (Nos. 1223, 1225). \i\ some (No. 

 1227) tho body is cylindrical and the pedicels are arranged in 

 five ambulacral zones, especially obvious near tho anus. In all, 

 dorsal appendages seem to have the end-plates more weakly 

 developed than in the ventral pedicels ; still in some they arc 

 tolerably well developed, while in others they are very small ; 

 in fact, it is very diflicult to make a clear distinction between 

 pedicels and papilla\ 



Calcareous deposits are tables and buttons. Buttons in groups 

 which are visible to the naked eye or at least under a hand lens. 

 In one specimen, tho groups measured in diameter 0.17, 0.24, 0.32, 

 0.40 mm. In the Ogasawara specimen (the larger cne of No. 1223), 

 the groups are in Ihe shape of rings. In some (No. 1224,) these 



are covered over with tables 

 so that at first sight they 

 appear more like groups of 

 tables than of buttons, while 

 in others they arc obvious from 

 the outside. The buttons are 

 either (i) complete and then 

 mostly provided with three 

 pairs of openings (textfig. 22 r) 

 or (ii) half- sided (f/). Occa- 

 sionally (iii) there are some 

 which arc reduced to tho 

 central red only with bent 

 ends, so that a short thick 



Textfig. 22. , , i 



„ . „ . , ,. , . , C-shape may be produced 



Ilool/iuni p'lrJalis : a, b. — iabks with si^iny j. « i 



ninrgin; i — tnblo with smooth mnrgin ; (? — hnlf- (NoS. 1229, 1133 \ TllCrC aro 

 sided l)utton ; f — ordii nry button ; f, ij — suppoiting 



ro<i.s seen from diiTeront sides. (x3oo). all sorts of mtcrmediato forms 



