76 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



The. above terms which were accepted by Mr. Bather in 1890,* and used 

 in his earlier papers "On the British Fossil Crinoids, were in January, 1892 t 

 abandoned by him and substituted by others. He stated that he found 

 certain difficulties in their application to Palgeozoic forms, and proposed in 

 place of them the following terms : — 



Primibraclis = our primary brachials, or Costals. 



First primibrach = " first costal. 



Second primibrach = '^ second costal. 



Primaxil = " axillary costal. 



Secundibrachs = " secondary brachials, or Distichals. 



Secundaxil = " axillary distichal. 



Tertiobrachs = " tertiary brachials, or Palmars. 



Quartibrachs = " brachials of the fourth order ) 



Quintibrachs = " brachials of the fifth order C Postpalmars. 



Sextibrachs = " brachials of the sixth order ) 

 Etc. Etc. 



This nomenclature is based upon the same principle as our own, and 

 even the names are not so very different considering that the terms "cos- 

 tals," "distichals," and "palmars" are proposed as equivalents of "primary, 

 secondary, and tertiary brachials;" but Bather proposed these terms for the 

 pinnuleless forms only, and brought out another terminology to be applied to 

 pinnule-bearing arms, viz. : — • 



Monostichals (First Order). Tetrastichals (Third Order). 



First monostichal. Tetraxil (Third Mainaxil). 



Second monostichal. Octastichals (Fourth Order). 



Monaxil (First Mainaxil). (Fifth Order). 



Distichals (Second Order). (Sixth Order). 

 Distaxil (Second Mainaxil). 



That the branching of pinnuliferous arms, as supposed by Bather, is 

 almost quite regular, is by no means the case. We frequently find among 

 Camerate Crinoids rays with three, five, six, seven, nine, and ten arms, 

 instead of two, four, or eight. In 8trotocrinus, there are rays with thirty 

 arms in the calyx, and the " Finials," which here comprise the plates 

 of the free arms, although given off from the fourteenth axillary, are 

 "Triacontastichals." Still more complicated is the case in 8teganocrinus, 

 Eucladocrimis, Eipidocriiius, and Melocrmus, in which, to the full length of their 

 rays, from the costals or distichals up, the brachials are developed into rigid 



* Ann. and Mag. Vol. V. p. 313. f Ibid., Vol. IX. pp. 54-61. 



