658 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



In 1902 Hubert Lyman Clark announced the discovery of myzostomes on some 

 ophiurans from southern Japan, and in 1905 Wheeler described a new species 

 entoparasitic in a starfish from southern California. 



August Reichensperger described a new species in 1906 from the West Indian 

 Isocrinus dccorus. 



In 1906 also Hubert Ludwig described an entoparasitic chsetopod, Ophiuricola 

 cynips, from a deep-sea ophiuran. While not related to the myzostomes, this 

 animal, nevertheless, is of considerable interest in connection with them. 



Several new myzostomes from southern Japan (including those parasitic on 

 ophiurans mentioned by H. L. Clark in 1902), the West Indies, and the Pacific 

 coast of North America were described by Jesse F. McClendon in 1906 and 1907; 

 and in 1908 Rudolf Ritter von Stummer-Traimfels gave a detailed account of two 

 forms which had been found on the crinoids brought back by the Discovery from 

 the shores of the Antarctic continent. 



In 1912 D. Fedotoff described a very extraordinary myzostome, which he 

 called Protomyzostoma polynephris, and which he had found entoparasitic in an 

 astrophyton or basket-fish, Goryonocephalus eucnemis. Recently he has given a 

 very detailed account of this type, and has announced its discovery in Gorgono- 

 cephalus arcticus in the Kara Sea. 



In 1915 Charles L. Boulenger described the myzostomes from the comatulids 

 collected by Mr. Cyril Crossland in the Sudanese Red Sea, among which he found 

 one new species. 



The anatomy and embryology of the myzostomes have engaged the attention 

 of many able investigators : the life history has been treated by Elias Metschnikoff 

 (1866) and John Beard (1884) ; the sexual conditions by Beard (1894 and 1898), 

 Wheeler (189-4, and especially 1896), and A. F. Coventry (1910) ; various phases of 

 the embryology by Wheeler (1895, 1896, and 1897), Kostanecki (1897, 1898, and 

 1905), and Carazzi (1904) ; and the general anatomy by Nansen (1885 and 1887), 

 von Wagner (1886), H. Pruho (1S92), von Stummer-traunfels (1903 and 1908), 

 Maidl (1910), G. Retzius (1910). Boulenger (1911 and 1915), and Fedotoff (1914 

 and especially 1916). 



The following list includes all the known species of myzostomes : 



MYZOSTOMUM HOROIX)GIUM VON GRAFF. 



Occurrence. Free-living. 



Hosts. According to P. H. Carpenter most probably Comatula rotalaria and 

 Comatula Solaris, but more likely Zygometra microdiscus and Zygometra elegans. 



Localities. Challenger Station 186, Prince of Wales Channel, Torres Strait 

 (lat. 10 30' S., long. 142 18' E.), 8 fathoms; and CJiattenger Station 187, off 

 Booby Island, Torres Strait (lat. 10 36' S., long. 141 55' E.), 6 fathoms; probably 

 also Challenger Station 190, in the Arafura Sea (lat. 8 56' S., long. 136 05' E.), 49 

 fathoms. 



Remarks. This appears to be the species mentioned by von Willemoes Suhm 

 as occurring on a large black and white comatulid in the Arafura Sea. 



