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Show 1882.] CLASSIFICATION OF THE COMATULCE. 737 of Ant. rosacea and Ant. eschrichti, or with the second brachials of Act. fimbriata and Act. multiradiata. In the case of Act. typica, the employment of a shorthand has been carried to such an extent by Prof. Bell, that he only makes provision for 20 out of the 80 or more arms that the species possesses. The P which is inserted into the formula for Act. nova-guinea is here omitted, and only two of the axillaries taken into consideration at all. Nevertheless the rays have been described by myself as dividing seven or eight times ; i. e. there may be no less than five axillaries beyond the palmars, all united by syzygy to the preceding joints as the palmar axillaries are ; while Loven * has figured a specimen with two axillaries beyond the palmars and has described the species as having 80 arms. Prof. Bell's formula, however, (1 A'RD?) takes no account of any palmars at all, much less of any thing beyond them, although Loven says " Rami secundi quatuor, Una paria, e brachialibus duobus" and goes on to speak of rami tertii, quarti, and quinti; but the presence of the D and nothing more in Prof. Bell's formula indicates that the total number of arms is never more than 20 and m a y be only 11 ! It will be evident from the classification detailed above, that the essential character common to all the seven species of group B is the union of the second and third radials by ligaments and not by a syzygy as in the three species of group A . Nevertheless five of the seven formulas given by Prof. Bell contain an R, which denotes that the radial axillary " is a syzygy." He surely cannot imagine that the radial axillaries which are united by ligament to the second radials are themselves syzygial joints as the distichal axillaries are. I have described the form of the axillaries in each of these five species, but have not said one word about their being syzygial joints. Such a condition, i. e. syzygial axillaries united by ligaments to the second radials, occurs in no Comatula with which I a m acquainted. Neither are the axillaries united to the second radials by syzygy, as in Act. Solaris and the other species of Group A, the formulas for all of which contain an R. It is therefore difficult to understand why the formulae for five of the species of group B should contain an R which is absent from those of the two remaining species. I can think of no reason for this except that in the diagnoses of these five species I have spoken of the "first ray-division " as consisting of three joints, the axillary with a syzygy. Prof. Bell, w h o appears to consider the primary number of rays as 10, and not five, as described by Miiller and myself, has perhaps understood the term "first rav-division " to mean the five undivided rays themselves, which consist of the first, second, and third (axillary) radials. I had hoped that this expression coming immediately after the statement " the rays (in the Miillerian sense) dividing" 2, 3, or more times, and preceded by the description of the radial axillary where the division occurs, would be interpreted as meaning the ten primary arms which are borne by the axillaries and are themselves eon-i 6'fv. af. K. Vet.-Akad. Fdrh. 1866, p. 230. 49* |
