ICHTHYOCRINIDAE . T) l 7 



two IBr very short and wide, meeting- and interlocking laterally by angular 

 margins, with a prominent node or ridge at the angles. All higher brachials 

 very short and wide. Column large, with excavate facet less than diameter of 

 basal rim; tapering slowly from the calyx and gradually changing from short 

 to longer and alternating columnals. 



This species is represented by two well-preserved calices from the Hamilton group at 

 Alpena, Michigan, and a nearly complete specimen with stem and arms from equivalent 

 strata at New Buffalo, Iowa. The latter is considerably flattened, so that the calyx appears 

 wider and more robust than in the others ; it is somewhat weatherworn in the lower part, 

 where the sharp angularity of the rays does not appear, but the sculpturing of the brachials 

 from the first axillary up is finely shown. The smaller calyx, cleaned from the soft limestone 

 matrix, has this angularity well preserved in the lower part. The two calices also show very 

 prominently the nodose projections at the margin of the brachials, so that in this respect we 

 have the structures completely represented. There can be no doubt as to the propriety of 

 referring these specimens to the rare genus Euryocrinus, with which they agree in all essential 

 structures, the anal side differing only in minor detail. The species differs from those of the 

 Carboniferous in its more elongate and less curved form, larger basals, and the sculpturing 

 upon the brachials. 



Types. Author's collection. 



Horizon and locality. Middle Devonian, Hamilton Group. The two calices are from the 

 top layers of the Traverse Group of the Hamilton at Partridge Point, near Alpena, Michigan, 

 where they were found by my venerated friend, the Reverend Dr. W. H. Barris, who pre- 

 sented them to me a short time before his death as a contribution toward the present work, 

 and to whose memory I have dedicated the species. The more complete specimen is from the 

 same horizon at New Buffalo, Iowa. No others have appeared in the large collections since 

 made from the Michigan region. 



Euryocrinus concavus Phillips 

 Plate XL, figs. 4-5 



Euryocrinus concavus Phillips, Geology Yorkshire, II, 1S36, p. 205, pi. 4, figs. 14, 15. — Austin and Austin, 

 Ann. and Mag. Nat. Hist. (1) X, p. 109. — Morris, Cat. British Fossils, Ed. 1, 1843, p. 52 (2d Ed., 

 1854, p^ 79). — Wachsmuth and Springer, Revision Palaeocrinoidea, pt. 1, 1879, p. 34. 



Actinocrinus concavus, D'Orbigny, Prodr. Pal. Stratigraphique, I, 1849, p. 156. 



Not Euryocrinus concavus, Rofe, Geol. Mag. (1), X, 1873, p. 263, pi. 11, figs, n, 11a, b. 



Type of the genus. 



Of rather small size. Calyx low, broadly expanding to IIBr 2 , where height 

 to width is 1 to 2.5 ; spread of calyx from base to IAx, 1 to 3. Plates smooth or 

 granulose ; sutures sinuous, with tendency to imbrication. Crown above II"Br 2 , 

 and column, unknown. Width of a specimen at IAx, 30 mm. ; base, 10 mm. 



IBB small, entirely within BB, and tending to become resorbed. BB small, 

 mostly covered by the column; post. B projecting beyond it. Anal series broad, 

 with rays arching over at about the third or fourth plate; iBr 1, exceptionally 

 2; extremely narrow, and scarcely rising above level of IAx; no illBr. Poste- 

 rior radials smaller than the others. IBr 3, increasing in width strongly from 

 radials up. Column facet large, involving BB and small part of RR. 



