546 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



In 1866 Dr. Wilhelm Bolsche described in detail a specimen of bennetti in the 

 Gottingen Museum which had been collected in the Loyalty Islands by Doctor 

 Graffe. He noted that Muller's original description was incomplete, and that, 

 through Professor Keferstein, he had had Herr Herklots, the conservator of the 

 Reichs-Museum in Leyden, make a comparison between his description and Muller's 

 original specimens in order to confirm the identification. 



It was this specimen which was studied by Prof. Hubert Ludwig, then at Got- 

 tingen, and which was mentioned by him in 1877 and 1879. 



In 1877 Prof. Christian F. Lutken listed Actinometra brachymera from Port 

 Denison and the Pelew Islands, but he gave no description of this new form. 



Dr. P. H. Carpenter in 1877 discussed the genus Comaster, considered as including 

 only Comaster multiradiatus Goldfuss, at great length. He said that the recent genus 

 Comaster, or Comatula multiradiata of Goldfuss, from the Indian Ocean, has been 

 considered by most authors generically identical with the fossil genus Solanocrinus 

 on account of the appearance of the basals on the exterior of the calyx. 



The condition of the central ends of the basals, however, and, in fact, of the 

 whole calyx, is very remarkable and very unlike that presented by any other comat- 

 ulid with which we are acquainted, while the differences between it and Solanocrinus 

 are so very great that it is difficult to understand how they could ever have been 

 regarded as belonging to one and the same genus. 



He remarked that the centrodorsal of Comaster is hemispherical, but its margin 

 is not infolded as a broad lip forming a wide superior ventral surface on which the 

 radials rest. These last bear the axillaries directly, without the intervention of any 

 IBr 1; which are always present in comatulids, and have very narrow inferior faces 

 that simply rest upon the thick rim of the hemispherical centrodorsal basin. The 

 inferolateral angles of every pair of contiguous radials are truncated, and the spaces 

 left between them when they are in the natural condition of apposition by their 

 lateral faces are occupied by the 5 triangular basals which rest on the rim of the centro- 

 dorsal basin, and are visible on the exterior of the calyx alternating with the radials, 

 just like the peripheral ends of the basals of Solanocrinus costatus. In this species, 

 however, the basals are longish rods of considerable relative width and are in contact 

 by their central ends, while in Comaster they are small triangular pieces from the 

 middle of the inner and lower edge of each of which there arises a toothlike process 

 in the shape of a small cartilaginous rod extending to the center of the centrodorsal, 

 which is grooved to receive it. 



He noted that Goldfuss did not describe anything that could be regarded as a 

 rosette in Comaster, and the small triangular basals would seem to be the ultimate 

 condition of the embryonic basal plates, with which they exactly agree in their 

 relative position. But the relations of their central processes are somewhat difficult 

 to understand. They can hardly be regarded as comparable, except in their inter- 

 radial position, to the rays of the basal star of the comasterids, for they lie in grooves 

 on the floor of the cavity of the centrodorsal basin and are apparently independent 

 of the radials, which have no extensive area of synostosis with the centrodorsal 

 piece as in the comatulids while from Goldfuss's account of them they do not seem 

 to be calcified, but instead to be more of a cartilaginous nature. 



