MONOGRAPH OF THE EXISTING CKINOIDS. 107 



Although in reality continuous with its exteiisions along the ventral 

 surface of the arms, for convenience the \'isceral mass is assumed not to extend 

 out farther than the second bracliial, this being the point at which it com- 

 monly ruptures on being detached from the animal. 

 Visceral skeleton.—A skeleton, in the form of scattered spicules, developed witliin 

 the visceral mass. 



Wachsmuth and Springer's Law. — See Law of Waclismuth and Springer. 



Wall-sided. — The ossicles of the division series and arm bases are said to be wall- 

 sided when they are closely appressed agauist each other, and their appressed 

 sides are sharply flattened (see figs. 43, p. 77, 88, p. 145, 94, p. 155, 96, p. 159, 

 99, p. 160, 100, p. 162, 101, 102, p. 163, and 558, pi. 5). 



Water pores. — (1) The madreporic pores. 

 (2) the intersegmental pores. 



Whorl. — Of cirri; a row. 



EXPLANATION OF SYMBOLS. 



In the description of a comatulid the number of the cirri is expressed bv Roman 

 numerals, and the number of their component segments by Arabic ; thus " cirri XVII, 

 25" means that the animal has 17 cirri, each ■ft-ith 25 segments. 



The division scries are designated by the letters "Br" preceded by the figure 

 (in Roman numerals) denotmg the numerical sequence of the series; thus "IBr" 

 refers to the primibrachs (figs. 1, p. 60, 3, p. 62, 29, p. 71), or the first division series 

 following the radials (R R), the " costals " of P. H. Carpenter's terminology in his later 

 works, or the "second and third radials" of the CJiaUenger reports; IIBr, orsecundi- 

 brachs (fig. 29, p. 71), is equivalent to Carpenter's "distichal series," IIIBr to 

 "palmar series" (fig. 29, p. 71), IVBr to "post-palmar series," etc. The individual 

 elements of the division series are indicated by so-caUcd uiferior numbers; thus 

 IIBrj means the "first distichal" or the first ossicle folJoMing the first division series 

 and IIIBrj means the second ossicle of the "palmar" or third division series. The 

 ossicles of the free undivided arm are referred to simply as brachials. 



It should be emphasized that the employment of these symbols is merely a matter 

 of convenience and docs not m any way imply an homology between division scries 

 bearuig the same designation ui different genera. 



The presence of a syzygj' is indicated by the use of the symbol " +"; thus 

 "IIBr 4(3 + 4)" means that the second division series (the sccundibrachs or "dis- 

 tichals") are composed of four ossicles, of which the third and fourth are united 

 by syzygy (fig. 29, p. 71V 



The outer pinnules of an arm arc numbered in regular sequence, P,, Pj, P3, P^, 

 etc.; the inner pinnules are lettered, Po, Pj, P^, P^, etc. (fig. 6, p. 63). The 

 IBr or "costal" pinnule (only found in the genus Eitdiocrinus) is given as Pc (figs. 

 S3, p. 136, 84, p. 137), the IIBr or "distichal" pinnule as Pu (fig. 81, p. 134, on the 

 outer side of the second ossicles above the first axillary), and the IIIBr or "palmar" 

 pinnule as Pp (fig. 81, p. 134, the two apparently small pinnules on the second 



