1882. ] CLASSIFICATION OF THE COMATULZ. 741 
briareus 3 AD? have the same formula, except as regards the 
number of joints in the cirri; but, for all I know, the one may have 
20 arms only and the other 40, 60, or more. Act. multifida is a 
many-armed form of this kind, having two joints in the palmar and 
subsequent ray-divisions. Miiller describes the number of arms as 
40-44, and I have seen individuals with even more; but Prof. Bell 
gives the species-formula as 3 A'DE, exactly the same as that of 
Act. trichoptera, which has no palmars and 20 arms or less! 
I cannot imagine what has led Prof. Bell to suppose that the 
radial axillary of Act. multiradiata “is a syzygy,” so that he has 
inserted an R into his formula. Miiller made no mention of it in 
his description of the type, as he did in the case of Acé. solaris and 
its allies; and in a memoir’ now three years old, after personally 
examining the type specimens at Paris, I placed the species in a 
group distinguished as follows—‘“ Second and third radials united 
by ligament only.” Surely Prof. Bell has not understood Miiller’s 
expression, “‘ Die axillaria der drme mit Syzygien,” to include the 
radial axillary also*, With this R omitted and a missing (P’) in- 
serted, the formula becomes 2A'DP(P')P ; but it gives no information 
whatever respecting the number of joints in the distichal and palmar 
series. When the distichal axillary “isa syzygy,” it is either united 
by syzygy to the preceding joint (Act. jukesi), or there are two joints 
below it, so that it is really the third distichal. This rule is an in- 
variable one ; but even supposing it to be known to the readers of 
Prof. Bell’s formule, the same does not hold good with the palmars. 
For the palmar axillary, which “isa syzygy,” may be the third of its 
series, as in Act. parvicirra and Act. bennetti, or the second, as in 
Act. multiradiata ; or, like the distichal axillary of Act. jukesi, it 
is syzygially united to the preceding joint, as in Act. typica. Prof. 
Bell’s formula, however, gives no information about this, and the 
special distinctive character of the multiradiata group is thus alto- 
gether lost sight of, unless No. 5 of the following Rules be under- 
stood as known; but Prof. Bell is silent upon this point. 
The weakness of his method of formulation is partly due to the 
following cause :—The same symbol (D or P) is used indifferently, 
whether there are three or two joints, the axillary with a syzygy, or 
two joints united by syzygy. I should say, however, that the figure 
indicating the position of the first brachial syzygy would in most 
cases explain to an experienced worker which type was meant, as 
is shown in the general rules stated below; but Prof. Bell gives no 
hint of this. 
The formula 3DP, which he gives for Act. parvicirra, would thus 
admit of any of the nine following explanations, the third brachial 
being a syzygy in all cases, and the two outer radials united by 
ligament. In the other two columns are recorded some existing 
species, the distichal and palmar axillaries of which are syzygies, 
1 Trans. Linn. Soe. 2nd ser., Zool. vol. ii, p. 27. 
2 The italics are mine, 
