740 MR. P. H. CARPENTER ON THE [ Dee. 19, 
absence of palmars or of any further ray-divisions. One finds the 
Same deficiency of information in the formule for the following 
species, viz. Antedon bimaculata, brevicuneata, elongata, flagellata, 
levicirra, macronema, palmata, regine, spinifera. Had I not ex- 
amined eight of these personally, I should be unable to classify 
them properly from Prof. Bell’s formule alone. The remaining one 
(Ant. regine) is an MS. species of his; and I am therefore unable 
to give it a place in the classified list of species which concludes 
this paper. 
The only irregular types to which Prof. Bell’s notation is at all 
applicable are those like Act. rotalaria, which have two distichals 
and three palmars, with a syzygy in the last axillary but not in the 
distichal one. He gives the formula of this species as 3 A'(P)=5 
but this tells us nothing as to the number of the distichal joints ; 
and Prof. Bell is unable to carry out his plan of inserting the sign / 
to indicate that the distichal axillary is not a syzygy, because it 
would not apply to the palmars. A specialist would know that 
there are only two forms of distichal series yet described in Actino- 
metra, viz. two joints, the axillary without, and three joints, the 
axillary with a syzygy; so that the omission of D from Prof. Bell’s 
formula would lead him to infer that only two distichal joints were 
present in the corresponding species. But Prof. Bell gives no hint 
of this fact for the benefit of the uninstructed collector ; and should 
an Actinometra ever be discovered with four distichals and three 
palmars (the last axillary a syzygy), instead of two palmars withont 
a syzygy (as is actually the case in one species), it would have the 
same formula as Act. rotalaria, though widely different from it in 
reality), 
When, however, the case of Act. rotalaria is reversed, and there 
are three distichals and two palmars, the distichal axillary having a 
syzygy and the palmar not, Prof. Bell’s notation is altogether 
insufficient. He cannot insert a P, because there is no syzygy in 
the palmar axillary ; and he cannot use the sign 4, because there 
is a syzygy in the distichal axillary. He is therefore obliged to 
content himself with making no mention of any palmars at all. 
Omitting the cirrus-characters, we find his formulse for the six fol- 
lowing species to be all of the same general type, viz. 3 A (or A’) D. 
The species are—Antedon briareus, A. decipiens, A. irregularis, 
and A. savignii, Actinometra trichoptera and A. multifida. All of 
them have three distichals with the axillary a syzygy ; but some of 
them, Ant. savignii and Act. multifida, also have two palmars, 
while others, like Act. trichoptera, have not. Prof. Bell, however, 
gives the same group-formula in each case, so that I am unable to 
refer his two species, Ant. decipiens and Ant. briareus, to their 
proper positions ; and I have only been able to place And¢. irregu- 
‘aris in my classified list, owing to his having kindly permitted me 
to examine it for myself. Both An¢. decipiens (3AD;) and Ané. 
? Tam here speaking only of the ray-divisions, and take no account of the 
characters of the cirri, which might or might not: be different in the two species, 
