A MONOGRAPH OF THE EXISTING CRINOIDS 79 



genus Actinometra. He had found that the groove about the periphery of the disk 

 in Actinometra is not continuous as he had at first thought. 



Three species were assigned to the subgenus Actinometra; these were Solaris 

 Lamarck (including imperialis J. Muller, pcct'maia Linne", and purpureaJ. Miiller), 

 rotalaria Lamarck, and wahlbergii J. Muller. 



Among the 15 species assigned to the subgenus Alecto four belong to the Comas- 

 teridae; these are echinoptera J. Muller, Jimbriata Lamarck, parincirra J. Miiller, and 

 multiradiata Linne". 



Species which he was unable to place either in Alecto or Actinometra because they 

 had been dried and the disk lost or distorted, or because the arms were intertwined 

 ventrally concealing the disk, or for some other reason, he referred simply to Comatula. 

 There were 17 of these, of which 9 belong to the Comasteridae. These 9 were 

 brachiolata Lamarck, rosea J. Muller, cumingii J. Muller, trichoptera J. Muller, 

 japonica J. Muller, multifida J. Muller, timorensis J. Muller, novae-Guineae J. Muller, 

 and bennetti J. Muller. 



Dujardin and Hupe" in 1862 gave the history of the genus Actinometra and said 

 that it scarcely differs from Comatula other than in having the anus at the center and 

 the mouth at the margin of the disk. Under the generic name Actinometra they 

 described four species, imperialis J. Muller (also described on another page as Comatula 

 Solaris), pectinata Linne", multiradiata Linn6, and wahlbergii J. Muller. They 

 also recognized the genus Comaster as distinct both from Comatula and from Actino- 

 metra and described as Comaster multiradiatus the specimen originally described and 

 figured by Goldfuss. 



Prof. C. F. Liitken in 1866 and subsequently adopted the generic name Actino- 

 metra for all the species known to hmi which now are assigned to the family Comas- 

 teridae. He never published anything in regard to his reasons for doing this. But 

 the fact that he made this distinction, and furthermore made it along the lines 

 subsequently elaborated by P. H. Carpenter, is evident from the lists of names of 

 comatulids published in the catalogues of the Museum Godeffroy at Hamburg. 

 In the catalogue published in 1866, we find Actinometra trachygaster, which is repeated 

 in 1869; in 1874 he listed Actinometra gracilis, Actinometra intricata, Actinometra 

 stellata, and Actinometra tenax, and in 1877 Actinometra brachymera and Actinometra 

 fusca. All of these names are nomina nuda, but all of them have been identified. 

 In addition to these, the names Actinometra guttata, Actinometra affinis, and Actinome- 

 tra macrobrachius are found with specimens identified by him. The species belonging 

 to all the other groups were assigned by Doctor Liitken to the genus Antedon. 



In an elaborate memoir on the genus Actinometra published in 1879 Dr. P. H. 

 Carpenter first definitely pointed out the features characteristic of the comasterids. 



In this memoir Carpenter quoted the following from an unpublished manuscript 

 of Professor Liitken: 



The lower or oral pinnules of Actinometra are always very different from the others, being 

 flagellif orm and presenting a more or less distinct serrature or comb (pinnulae orales prehensiles) ; 

 while in Antedon they are only slightly differentiated from the others, or are transformed into strong 

 rigid spines, forming a protective covering over the disk. 



