346 THE VOYAGE OF H.M.S. CHALLENGER. 



and Miiller's other species, Actinometra japonica, to which I would now refer — possibly 

 as a varietal form — the individual which I called Actinometra morsei when asked by 

 von Graff to name the host of Myzostoma nigrescens. 



' This is a little specimen without palmars, which are also absent in most of the examples 

 of Actinometra trichoptera that I have seen. It has rather shorter axillaries than the 

 type of Actinometra japonica, and less developed spines on the terminal cirrus-joints, 

 both of which are points of resemblance to Actinometra trichoptera. It seems, however, 

 to have longer arm -joints than the Australian species, and shows the carination of the 

 large basal joints of the distal pinnules, which in Actinometra japonica extends further 

 out on the arm. This does not appear in Actinometra trichoptera, and for the present, 

 therefore, I should be inclined to regard the two species as distinct, though it is by no 

 means improbable that other intermediate forms may eventually be discovered. 



8. Actinometra littoralis, n. sp. (PI. LXVII. figs. 1, 2). 

 Specific formula — a.3.3.(2).— . 



Description of an Individual. — Centro-dorsal a very thin pentagonal disk with 

 slightly incurved sides, rather above the level of the radial circlet and separated from 

 it by faint clefts. Cirri all lost. Three radials visible ; the second almost completely 

 united laterally, but the axillaries free. The rays may divide four times. Three 

 distichals and three palmars, the axillary with a syzygy ; post-palmars, when present, 

 of two joints only, the axillary without a syzygy. Thirty-eight arms, which are all 

 grooved, but dimorphic. The anterior of one hundred and fifty, and the posterior of 

 one hundred segments, which are triangular at the base, gradually becoming more 

 quadrate and slightly elongated towards the end. Syzygies in the third and tenth or 

 eleventh brachials ; others at intervals of three or four joints. 



The palmar pinnule is nearly as long as the distichal one, which reaches 12"5 mm.: 

 but that of the second brachial is much shorter. The next pair are the smallest, their 

 successors increasing again. The terminal pinnules are much longer and more slender in 

 the anterior than in the posterior arms. The lowest joints of the proximal pinnules are 

 rather wide and overlap slightly with spinose margins. The proximal pinnules have a 

 well-defined comb which disappears by the fourth or fifth brachial. 



Mouth interradial ; all the arms grooved ; disk naked. 



Colour in spirit, — deep blackish-brown. 



Disk 20 mm.; spread 20 cm. 



Locality. — Banda ; 17 fathoms. One specimen. 



Remarks. — But one individual of this species having been obtained, I am unable to 

 state its characters as definitely as I could wish. In the normal arrangement of the arm- 



