36 SMITHSONIAN INSTITUTION 



with the secundibrachs, the first four brachials were syzygial pairs. Or it 

 may be considered that the first two pairs of secundibrachs were simply repeti- 

 tions of the primibrachs, with the second plate of each pair an axillary, analo- 

 gous to what is seen in the divisional series of Recent crinoids, as pointed out 

 by Mr. Austin H. Clark in his luminous paper on the Homologies of the Arm- 

 joints and Arm-divisions in the Recent Crinoids. 1 



The tegmen. — This is not shown in any of our specimens, but it is cer- 

 tainly composed of numerous undifferentiated plates with the anal opening 

 directly through it; and is doubtless substantially the same as that of Glypto- 

 crinus, as shown by figure 5& of Plate III. It must extend quite high along the 

 rays, doubtless to the quartibrachs, and these upper extensions may be composed 

 almost entirely of the consolidated pinnules. Several specimens show where 

 the interbrachial pavement begins to curve rapidly to the tegmen, and at this 

 level the pavement is composed exclusively of fixed pinnules (PI. IV, fig. 1). 

 Messrs. Waagen and Jahn say that the tegmen (voute) is unknown in the 

 genus, but they direct attention to certain voutes isolees, figured on their plates 

 49 and 64, of which they have not been able to find the calyx corresponding. 

 I have no doubt that these belong to some of their varieties of the genus, and 

 they clearly show the tegmen to be of the structure above indicated. 



The stem. — The full length of the stem is not certainly known, but it was 

 at least 3 feet (90 cm.). Among the Bohemian specimens described by 

 Waagen and Jahn it was rare to find any part of the stem attached, but Pro- 

 fessor Jahn in a letter to Mr. Schuchert quoted by him (op. cit., p. 259) 

 states that he has " observed at Kuchelbad on the exposed surfaces of the 

 strata Loboliths connected by long columns to Scyphocrinus calices." Schu- 

 chert (op. cit., p. 262) records having seen at the same locality near Kuchelbad, 

 Bohemia, a poorly preserved theca of Scyphocrinus with a " long column 

 probably not less than 3 feet in length, extending toward and terminating 

 upon a Caniarocrinus." This evidence seemed to him at the time so convinc- 

 ing as to remove all doubt of " Scyphocrinus and Caniarocrinus belonging to 

 one species." But a further study of the stem characters led him to revise 

 this opinion as follows: " The writer observed that the long column of Scypho- 

 crinus lying across the Caniarocrinus was at least twice as thick as any column 

 of the latter he had seen. Since then he has determined that the central canal 

 in the column of Caniarocrinus is different in shape and very much smaller in 

 size than in the associated Scyphocrinus columns." These differences he 

 illustrated by text-figure 42, showing transverse sections through the stalk of 

 Scyphocrinus elegans near the theca, and a thick stalk of Caniarocrinus ulrichi 

 near the roots; the latter is about half the diameter of the former, and has a 

 small, sharply stellate, axial canal, contrasted with a large quinquelobate canal 



1 Proc U. S. National Museum, vol. 35, pp. 113-131, 1908. 



