KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 2. 37 



tion. Although Mr. floHN Gray was liberal in the distribution of casts of the specimen 

 that gave rise to this figure, nevertheless the fractured and distorted condition of the 

 specimen, and the anomalous character of the whole structure still left much room 

 for doubt. 



In 1878 Prof. Angelin 1 ) gave a new diagnosis of the genus, under the name 

 Myelodactylus, which may be rendered thus. — Crown narrow, elongate; dorsal cup cup- 

 shaped. IB, 3. BB, 5, polvgonal. RR, 5. IBr, 2; IBr 2 axillary. Anal plates (»Interradialia») 

 2. Anns very long, subfiliforni, repeatedly dichotomous, with simple ossicles. Ventral 

 tube distinct, jointed. Stem thick, eoiled, with very fine ossicles and numerous monili- 

 form cirri. To the genus he referred three supposed new species, viz. — 



M. heter ocrinus, Tab. X, figs. 24, 25. Crown with arms more stout than in 

 M. gracilis. Cirri thick, close-set, in single series. Length 37 mm. Fol- 

 lingbo. M. R. 

 M. gracilis, Tab. X, fig. 28. Cup elongate, narrow. IBr 3 very large, bearing 

 2 branches. Arms graceful and elongate, many times divided. Cirri monili- 

 form, embracing crown. Length of crown 30 mm. Visby. M. R. 

 M. interradialis, Tab. X, figs. 26, 27. Cup cup-like. IB obsolete. BB 5. Anals 

 6 in single series. Petesvik. 

 The value of these species will be discussed låter on; meanwhile we shall see what other 

 observers have gathered from his work. Angelin placed the genus in his family Taxo- 

 crinida?. 



In 1879 Prof. K. A. v. Zittel 2 ) gave a diagnosis of the genus compiled from Hall, 

 Salter and Angelin, and left it in the Taxocrinida\ 



In the same year Messrs. Wachsmuth and Springer 3 ) treated Myelodactylus as a 

 doubtful genus. They considered with Hall that Hall's figures represcnted portions of 

 arms, but remarked, — »We cannot see any propriety in founding genera or species upon 

 mere fragments of arms or column, especially i ii a case like this:. They could not under- 

 stand why Angelin referred his three species to this genus, and pointed out witli justice, 

 that only M. hetevocrirms agreed witli Angelin's generic diagnosis. They continued, — 

 We have here placed Myelodactylus pro\ isionally under the Cyathocrinidw, because An- 

 gelin's first two species iindoubtedly belong to that family, though probably to different 

 genera. His M. (?) interradialis, however, is a representative of an altogether different 

 family». Species founded upon mere fragments of column were not recognised by Wachs- 

 muth and Springer; and it appears that they felt unable to adopt Halls genus, but 

 provisionally adopted Angelin's with M. heterocrihus as typé. This seems a logical pro- 

 ceeding so far as it goes. 



In 1880 Mr. S. A. Miller 4 ) described a species of this genus under the name 

 Myelodactylus bridgeportensis. Unfortunately his material was all in the form of casts 

 from magnesian limestone, and this led him into some very remarkable errors as to the 



') Iconographia, p. 11, Tab. X, tigs. 24 — 28. 



2 ) Handb. d. Palaeont., vol. I, p. 354. 



3 ) Revision I, (145), Proc. 1879, p. 308. 



4 ) Jouni. Cincinnati Soc. Nat. Hist., vol. III, p. 141; July, 1880. 



