242 SMITHSONIAN INSTITUTION 



their presence or absence ; and that " if Forbesiocrinus is to be retained as a distinct genus 

 from Taxocrinus, it will have to be separated upon some characters or differences not yet 

 observed." But they proposed to continue to use the two names — Forbesiocrinus in a sub- 

 generic sense — for the sake of convenience, ranging under Taxocrinus species without 

 interradial or anal pieces as well as those with one or two each, and under Forbesiocrinus 

 those with a greater number of such pieces. In 1871, Professor Beyrich (Monatsber. K. 

 preuss. Akad. Wiss., Berlin, Feb., p. 43) expressed the opinion that the separation of the 

 two genera could only be maintained if Taxocrinus were limited to those species in which 

 the first division of the radii takes place in the third joint, while four primary radial segments 

 are characteristic of Forbesiocrinus. This would exclude nearly all the Carboniferous 

 Taxocrini, among them the most typical species of Phillips. 



In 1878 Wachsmuth and Springer (Proc. Acad. Nat. Sci. Philadelphia, p. 254), dis- 

 cussing the relations between the two genera in connection with the new form " Ichthyo- 

 crinus " nobilis, doubted whether they could be separated, even subgenerically. But in 1879 

 (Rev. Pal., pt. 1, p. 43) we reviewed the subject at some length, and pointed out the fact that 

 in the forms considered to be Taxocrinus, being species with but few interradials, the anal 

 plate had a truncated upper margin and was succeeded by from two to six similar, narrow, 

 quadrangular plates longitudinally arranged ; that these formed the dorsal side of a short 

 and slender lateral proboscis whose ventral parts, as well as the wall supporting them, had 

 never been found preserved, and evidently consisted of more fragile material ; and further 

 that among the species referred to Taxocrinus were not only those with few or no inter- 

 radials but some with a comparatively large number. And we concluded that while on the 

 anterior side of the latter specimens the construction seemed almost identical with that of 

 Forbesiocrinus, " their posterior aspect exhibits in Taxocrinus a small lateral proboscis, while 

 in Forbesiocrinus the space is filled with heavy plates ; in the latter an almost pentamerous 

 symmetry, in Taxocrinus .... a distinct bilateral one. This we consider the best distinc 1 

 tion between the two genera " (ibid., p. 47). 



Von Zittel recognizee! the genus, both in his Handbuch, 1879, and in the Grundziige, 

 1895; and in Zittel-Eastman's Text-book, 1896, following the above conclusion of Wachs- 

 muth and Springer, it was stated (p. 164) to differ from Taxocrinus in the construction of 

 the anal area. In the North American Crinoidea Camerata, 1897, however, the subject was 

 further complicated by a remark of Wachsmuth and Springer in a note to page jy to the 

 effect that the Belgian species on which De Koninck and Le Hon founded the genus belongs 

 to Onychocrinus. Bather in Lankester's Zoology, 1900, does not recognize Forbesiocrinus 

 as a genus, but on page 190 mentions "Forbesiocrinus agassisi" which he says may be placed 

 in the family Sagenocrinidae ; adding that " patelloid plates are richly developed, but are 

 absent from Sagenocrinus. Otherwise the two genera agree closely." This course was in 

 harmony with my own opinion then held, as already stated under the genus Sagenocrinus, 

 and in 1901 (Uintacrinus, Mem. Mus. Comp. Zoology, vol. 25, p. 71) I stated my belief that 

 " the name " Forbesiocrinus " will have to be given up, as suggested by Bather. The English 

 species taken by De Koninck as type is a Taxocrinus pure and simple, while the two speci- 

 mens figured by him from Belgium surely belong to the type for which the genus Onycho- 

 crinus has been established." Subsequent investigation, with the aid of the new material 

 above mentioned, led me to reconsider this opinion both as to the validity of the genus 

 Forbesiocrinus and the reference to Onychocrinus, which was a reiteration of the expression 

 of 1897 above cited founded upon a misconception of the specimen now figured on Plate 

 XXIII, figure ia, as already explained. This resulted in the conclusion stated by me in 1902 

 (Amer. Geologist, vol. 30, p. 90) which will be here restated : 



Bearing in mind Wachsmuth and Springer's description of the anal side of Taxocrinus, 

 and remembering that this is the main character upon which the entire family Taxocrinidae 



