390 Mr. P. H. Carpenter. Preliminary Report upon [Mar. 6. 



all the other Comatulce it is circular or pentagonal, more or less convex, 

 and marked with several cirrhns sockets, either only at the margin or 

 all over its surface, while the cirrhi are rarely so imperfect' as in 

 Loven's specimen. 



Among the Comatulce in the British Museum is a specimen labelled 

 Actinometra stellata, Ltk. It had been purchased from the collection of 

 the Godeffroy Museum, having been previously examined and named 

 by Dr. Llitken . 



The mouth is not central as Loven describes it in Phanogenia, but 

 eccentric, though comparatively only but slightly so. The condition 

 of the centrodorsal, however, is essentially similar to that presented 

 by Phanogenia, and it was this feature, I do not doubt, that caused 

 Liitken to give the specific name stellata. to this type. The stellate 

 condition of the centrodorsal in Phanogenia has long been a puzzle to 

 me, and I am therefore glad to be able to say that the material brought 

 home by the " Challenger " throws a considerable light upon it. This 

 condition appears to be one of the concluding stages of a long series of 

 changes in the shape and relations of the centrodorsal, which do not 

 commence until some time after the loss of the stem, and the entry 

 upon the free state of existence. 



The "Challenger" dredgings in Torres Straits brought up a con- 

 siderable number of specimens of a hitherto undescribed Comatula. 

 This species was first discovered by the late Professor Jukes, who 

 brought home specimens and deposited them in the British Museum. 



1 propose, therefore, to name it Actinometra Jukesii. The " Challenger " 

 collection contains nine young specimens of this species, most of 

 which have cirrhi on the centrodorsal. But in the adult the centro- 

 dorsal is a pentagonal plate four millims. in diameter, without a trace 

 of cirrhi or even of cirrhus sockets. Its surface is level with that of 

 the radial pentagon within which it is enclosed. 



Stage 1. In the youngest specimen the centrodorsal is a nearly 

 circular plate 1*5 millims. in diameter, just sufficiently raised above 

 the surface of the radial pentagon to bear about eight marginal 

 cirrhi. 



Stage 2. In others from the same locality which have a centrodorsal 



2 millims. in diameter, it bears no cirrhi, and the sockets are partly 

 obliterated, while the height of the plate above the rest of the calyx 

 is somewhat reduced. Three other specimens, however, of the same 

 size which were obtained at Cape York on another day, still retain 

 their cirrhi. 



Stage 3. By the time that the diameter of the centrodorsal increases 

 from 2 to 2"5 millims., its shape becomes more distinctly pentagonal and 

 scarcely any trace of cirrhus sockets is visible, the plate being so thin 

 that it rises very little indeed above the level of the radials. In one 

 specimen of this size there is one rudimentary cirrhus stump and two 



