REPORT ON THE CRINOIDEA. 43 



would have enabled him to separate types that are placed very near to one another in 

 his scheme. Thus, for example, Comatula palmata and Comatula macronema are placed 

 respectively next to Comatula japonica and Comatula reynaudi, though the distichal 

 axillary is the second joint above the radials in the first pair, and the third (or, counting 

 the syzygy, the fourth) joint in the second pair. It soon appeared to me to be a very 

 general rule among Comatulse that " the first and second segments beyond every 

 axillary, whether radial or brachial, are nearly always united together in the same manner 

 as the second and third (axillary) radials." 



These observations rendered the classification of the Comatulas which were then known 

 (1879) a comparatively easy task; and during the next three years I described several 

 species both o£ Antedon and of Actinometra, arranging the multibrachiate forms according 

 as there were one or two joints between the successive axillaries of the arms, and by the 

 presence or absence of syzygies in these axillaries. The most common arrangements of 

 the arm-divisions are the following — two joints, the second axillary without a syzygy, 

 and three joints, the second bearing a pinnule, but the third axillary with a syzygy. 

 These of course would have been equally well distinguished in Midler's classification 

 according to the presence or absence of syzygies in the axillaries. But in Midler's 

 scheme there is no separation from the second of these types of species like Actinometra 

 sentosa (PI. LX VI. fig. 4) in which all the outer arm-divisions consist of two joints only, 

 but the axillaries are syzygial joints just like those of Actinometra japonica, or Antedon 

 reynaudi. In like manner Midler's classification provides no place for forms like 

 Actinometra paucicirra, in which the axillary is not itself traversed by a syzygy, but is 

 united to the preceding joint by syzygy instead of by an articulation (PI. LIV. figs. 1, 2). 



If these characters be taken into account, and especially the mode of union of the two 

 outer radials, whether by articulation or by syzygy, the numerous multibrachiate species 

 of Antedon and Actinometra may be readily separated into comparatively large groups, 

 for the further subdivision of which a more detailed examination of anatomical characters 

 becomes necessary. 



In the year 1882 Professor F. J. Bell : attempted " to apply a method of formulation 

 to the species of the Comatulidee." He stated that the leading differences between the 

 radial, distichal, and palmar series in different species of Comatulse " are to be found in 

 the varying arrangement of that mode of union to which Johannes Midler applied the 

 term syzygial" ; and he therefore inserted the letter R, D, or P into his formula 

 " whenever the respective axillary is a syzygy," placing before this letter and the generic 

 symbol the figure 1, 2, or 3, according as the first, second, or third brachial is a syzygial 

 joint. Bell further devised a very convenient method of briefly indicating the number of 

 joints in the cirri and also that of these organs themselves. I have been glad to adopt 



1 An attempt to apply a Method of Formulation to the Species of the Comatulidc-e ; with the Description of a New 

 Species, Proc. Zool. Soc. Lond., 1882, pp. 530-536. 



