SAGENOCRINIDAE 2.YJ 



species is one of the most striking fossils of the famous locality at Dudley, England, where 

 it was not uncommon ; and good representatives of it were to be found in most of the promi- 

 nent collections in England. 



D'Orbigny in his Prodrome Paleontologie, vol. i, 1849, p. 46, ignored Austin's genus 

 altogether, and referred Phillips's species to Glyptocrinus, in which he was followed by 

 Murchison in 1859 in Siluria, p. 247. Bronn in the Lethaea Geognostica, 1851-6, vol. 1, p. 22, 

 referred the genus to the Periechocrinidae of Austin ; while Roemer in the same volume, 

 p. 228, placed it under a family of its own, as did Angelin in 1878. Pictet (Traite Pal., vol. 4, 

 1857, p. 323) placed it under his second tribu, Actinocriniens. Von Zittel in 1879 (Handb. 

 d. Pal., vol. 1, p. 375, and Grundziige Pal., 1895, P- I 3°) referred it to the Glyptocrinidae. 

 Angelin (Icon. Crin. Suec, 1878, p. 8) for the first time gave a description and figures show- 

 ing the construction of the calyx, on the strength of which Wachsmuth and Springer (Rev. 

 Pal., pt. 2, 1881, p. 201), though noting a resemblance to Taxocrinus, ranged the genus under 

 the Rhodocrinidae. They considered Angelin's statement of " sex parabasalia " to be a mis- 

 take ; but they could not believe the sixth plate to represent an anal, " as no plate of that kind 

 has ever been observed below the line of radials." 



When in England in 1887-88 I had for the first time an opportunity to see and obtain 

 good specimens of Phillips's species, and was immediately convinced that their relationship 

 was with the Flexible crinoids ; in a note to our paper on the ventral structure of Taxocrinus 

 (Proc. Acad. Nat. Sci. Phila., 1888, p. 357) Wachsmuth and I referred the genus to the 

 Ichthyocrinidae, in which family the whole group was then included. 



After all the shifting of opinion as to the systematic position of this genus, and its final 

 settlement in a firm place among the Flexibilia, it is interesting to note that this relationship 

 was perceived as early as 1841 by that sagacious observer, John Phillips, who when proposing 

 for certain species his Taxocrinoid genus under the preoccupied name Isocrinus (Pal. Foss. 

 Cornwall, p. 29) said : " Perhaps Actinocr. ( ?) expansus, of Sil. Researches, may be allied to 

 them." To a similar effect was the suggestion of De Koninck and Le Hon in proposing their 

 genus Forbesiocrinus (Crin. Carb. Belgique, 1854, p. 121, note), that "it is not impossible 

 that Actinocrinus ? expansus, Phill., belongs to this genus." 



So much was I impressed with the resemblance of the Dudley specimens to the American 

 Forbesiocrinus agassisi that I was disposed, in view of the doubts as to the validity of the 

 name " Forbesiocrinus," to think that all the American species described under it might be 

 referred to Sagenocrinus ; a view which was substantially taken by Bather (1900, Lankester's 

 Zoology, pt. 3; p. 190), and which I afterward expressed in 1901 (Mem. Mus. Comp. Zool., 

 vol. 25, no. i, p. 71). In these views both of us, as well as all previous writers, overlooked 

 the significance of the " sixth parabasal " of Angelin, which instead of being a mistaken 

 character, as too hastily supposed by Wachsmuth and Springer, is a constant element in all 

 the specimens as the radianal within the ring of basals — one of the most remarkable and 

 distinctive characters to be found in this entire group. This was pointed out by me in 1902 

 (Amer. Geologist, vol. 30, pp. 89, 94), and the distinction between the two genera clearly 

 shown, in connection with the description of an American species from the Niagaran of 

 Waldron, Indiana. This species, as there stated, is not fully characteristic in the position of 

 the radianal, which does not touch the infrabasals although occupying substantially the same 

 relative position. Since that time, however, a species having all the characters of the English 

 and Swedish specimens has been found in the American Silurian, so that the geographical 

 range of the genus is confirmed by an unquestionable species. 



In default of any constant diagnostic characters for separating them the English and 

 Swedish forms must remain together under the type species as Angelin placed them, while 

 those from America may be distinguished as indicated in the following analysis : 



