740 MR. p. H. CARPENTER ON THE [DcC. 19, 



absence of palmars or of any further ray-divisions. One finds the 

 same deficiency of information in the formulae for the following 

 species, viz. Antedon bimaculata, hrevicuneata, elongata, flagellata, 

 IcEvicirra, macronema, pnlmata, regince, spinifera. Had I not ex- 

 amined eight of these personally, I should be unable to classify 

 them properly from Prof. Bell's formulae alone. The remaining one 

 {A7it. regince) 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 iu the last axillary but not in the 

 distichal one. He gives the formula of this species as 3 A'(P)^; 

 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 V 

 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 Aetino- 

 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 without 

 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 sj , because there 

 is a syzygy in the distichal axillary. He is therefore obhged to 

 content himself with making no mention of any palmars at all. 

 Omitting the cirrus-characters, we find his formulae 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 Ant. irregu- 

 laris in my classified list, owing to his having kindly permitted me 

 to examine it for myself. Both Ant. decipiens ("SAD^^ and Ant. 



* I am here speaking only of the ray-divisions, and take no account of the 

 characters of the cirri, which might or might not be different m the two species. 



