166 COLLECTIONS FKOM MELANESIA, 



fornily purple, while the other has the purple relieved by a white 

 median dorsal line and by some white pinnules. 



I trust that with an increase in our knowledge and with a larger 

 series of specimens the preceding discussion will he found, long as it 

 must have seemed, to he of some aid in the determination of the 

 characters and limits of the species; wilh such scanty information 

 as we possess at present it would be to the last degree rash to 

 venture on any kind of prophesy. "Were I to make one, however, 

 I should say that many of the variations, which at present there is 

 a tendency to regard as of specific importance, will be found to 

 present less constancy of arrangement when large series are brought 

 together for examination. In the work of enlarging our knowledge 

 of the species of Crinoids the British Museum may well look to 

 those English colonists who live on such sea-boards as that of the 

 Australian coasts, and who have opportunity to do some dredging 

 in their waters. 



The student will believe that it was not without much study that 

 I instituted the species now succeeding ; since I did so I have had 

 the opportunity, thanks to the kindness of Mr. E. P. Eamsay, of 

 examining a collection of Australian Echinoderms : and it was with 

 a certain amount of satisfaction that I obtained from it specimens 

 which exhibited a close resemblance to A. intermedia, and led me 

 to think that I was justified in regarding its differential characters 

 as constant and definite. 



Standing midway between A. Solaris and A. rohusta it may be 

 distinguished as 



17. Actinometra intermedia. 



As Mr. Carpenter has pointed out, it appears to be possible, in 

 part at any rate, to distinguish A. Solaris from A. robusta by the 

 character of the keels, which, in the former, are so strikingly de- 

 veloped on the basal joints of the second pinnule. Basing myself on 

 the theory that the keel is constantly present on the basal joints of 

 the second pinnule of A. Solaris (Plate XVI. fig. A, a), and that it is 

 never found on those of A. robvsta (fig. A, b), I venture to think that, 

 in the case of A. intermedia, we have to do with a form in which 

 constantly the keels are never as well developed as in A. Solaris, 

 and never so slightly as in A. robusta, while at the same time there 

 are considerable differences in the extent of the development of the 

 keel, not only within the limits of the species but even of the indi- 

 vidual (cf. figs. A, c, d). 



The following appear to be the more characteristic marks of the 

 species : — A general resemblance to A. Solaris; but there are about 

 18 cirri, with from 18-20 joints ; first pinnules not specially long, 

 of rather more than 40 joints ; basal joints of second pinnules 

 with a not conspicuous keel, and with one which varies in the 

 extent to which it is developed. Arms widest a slight distance 

 from the disk. 



