MONOGKAPH OF THE EXISTING CRINOIDS. 657 



Sven Loven in 1840 and in 1842 published additional information regarding 

 the myzostomes of Antedon, and in 1858 Semper and also Diesing contributed to the 

 knowledge of the Mediterranean species, both describing several new forms. 



In 1875 and 1876 C. Th. E. von Siebold published letters which he had received 

 from R. von Willemoes-Suhm, one of the young naturalists on board the Challenger. 

 In these letters which, having been written on shipboard by a youthful enthusiast, 

 to whom everything was new and interesting, in the midst of the activities of the 

 first great expedition for marine exploration, breathe the spirit of marine investi- 

 gation to a degree which can never be attained by one who writes in the seclusion 

 of the home from half-forgotten notes taken in the field, various encysting 

 myzostomes are described, dioecious species are recorded, and remarks on the general 

 biology of these animals are included. 



The year 1877 saw the completion of Ludwig Graff's (later von Graff) mono- 

 graph on the genus Myzostomum (emended by him to Myzostoma), in which all 

 that was known about these creatures was included, and in which a considerable 

 number of new forms, largely from the Philippines, were described. 



The appearance of this work at once called attention to Graff as the leading 

 authority on the myzostomes, and the authorities in charge on the material collected 

 by the numerous British exploring expeditions, actuated by the unselfishness and 

 absence of narrow nationalism which has always characterized the scientific men 

 of Britain, promptly turned over to him all the myzostomes in their possession. 

 Thus between 1883 and 1887 he was enabled to publish reports upon the myzostomes 

 of the Porcupine, Triton, and Challenger expeditions, his two volumes on the last 

 remaining to this day the most voluminous and extensive contributions to the 

 knowledge of the group from the systematic and distributional standpoint. 



On the original specimen of Metacrinus rotundus, which had been dredged in 

 Sagami Bay, Japan, by Ludwig Doderlein, P. H. Carpenter found an interesting 

 myzostome, which von Graff described in 1885. In the same year he called atten- 

 tion to certain deformities in fossil crinoids, and suggested that they might have 

 been caused by myzostomes. 



In 1885 P. H. Carpenter noticed certain cysts in the arms and pinnules of 

 Antedon which he thought were caused by myzostomes, but they were shown by 

 von Graff in 1887 to have a different origin. 



In 1886 von Graff described some new myzostomes which were found on the 

 comatulids in the Zoological Museum at Copenhagen ; and in 1887 F. von Wagner, 

 one of his students, described a curious new form which he had found associated 

 with Antedon adriatica on the Dalmatian coast. 



Up to 1895 all the known myzostomes were parasitic upon the crinoids. and 

 were either free-living or inclosed in cysts which, more or less developed, opened 

 to the exterior. In that year Emil von Marenzeller made known a new type, 

 Myzostomum asterice, which lives as a true endoparasite in certain starfishes. 



In 1896 William Morton Wheeler, in a paper primarily on the sexual phases 

 of the myzostomes, described several new species which he had found on penta- 

 crinites in the British Museum. 



