G2 Mr. F. A. Bather— Suggested 



Batocrinus Lovei (the formula for all rajs except anterior). 



lax2.llax2.inBr-2.4St, 

 or, more shortly, l-lll Brj . 4 St. 



This is quite clear, tlie only point to notice being that in 

 the third order of brachials two are fixed, the rest free and 

 pinnuliferous. The corresponding formula for Batocrinus 

 Christyi is 1-111 axj . 8 St. 



Gilhertsocrinus tuherculosus. 



lax2.11ax3.IlIax^..8St. 



In this case tlie tertiobraclis are free but bear no pinnules, 

 and there are 8 pinnulate arms to each ray. 



One cannot hope to express quite as much in a formula as 

 ]Mr. Puff got into a sliake of Lord Burleigh's head ; it is hoped 

 nevertheless that the above examples will show how, by a 

 more rational terminology, with its appropriate symbols, the 

 attempt to apply a system of formulation to Palaeozoic 

 Crir.oids may have some chance of success. There are of 

 course more comjdicated plans of arm-brancliing than those 

 here alluded to; they will demand more complicated formula? 

 no doubt, but it should be possible to use the same terminology 

 and symbols in all but the most exceptional cases. 



In terradia I Pla tes. — In terhrachia Is. 



The term " Interradials " is applied by "Wachsmuth and 

 Springer to " all plates interradially disposed in the calyx." 

 These include Basals, Interradials (s. str.), Interambulacrals, 

 and Orals. Kow, since all these ])lates are truly interradial^ 

 and since all morphologists will wisii to retain this wide use 

 of the Avord, it seems a pity to endeavour to restrict it to those 

 interradially situated plates alone that occur in tlie dorsal cup 

 and that are above the level of the basals. There is a term 

 " Interbrachials," Avhich Wachsmuth and Springer have 

 proposed " for all plates between the rays above the radials," 

 thus, by implication, still further limiting the meani-.ig of 

 Intenadials [s. atr.) to the one ])late in each interradius that 

 may occur between the radials themselves. But morpho- 

 logically these latter plates do not differ from the Inter- 

 brachials (W. &, Sp.) in the same way as radials differ from 

 brachials ; consequently the difference of name is misleading. 



