Figure 2 . Photographs of examples from the Iocrinus trentonensis and Rhaphanocrinus subnodosus assemblages from the Walcott-Rust Quarry; both specimens from MCZ and coated with ammonium chloride. 1, Iocrinus trentonensis assemblage with 113626, note partial disarticulation of I

Figure 8. Iocrinus trentonensis Walcott, 1883 and Cremacrinus guttenbergensis Kolata, 1975 : ( 1–3 ) Iocrinus trentonensis ; ( 1 ) two partial specimens (note arm branching on the larger specimen and aboral cup shape on the smaller specimen), UMMP 74667.1–74667.2; ( 2 ) CD interray view

Figure 4 —Figured specimens of Iocrinus trentonensis from Walcott-Rust Quarry with holdfasts consisting of distal stem coils wrapped around the columns of other crinoids; all specimens from MCZ and coated with ammonium chloride, ×3.2. 1, 2 , Stem coils that are largely intact, 113655 and 172809

Figure 2 —Figured specimens of Iocrinus trentonensis from Walcott-Rust Quarry showing cups, stems, arms and anal tubes; all specimens from MCZ and coated with ammonium chloride. 1–3 , Arm fragments with wide food grooves and large covering plates, ×5.9; 1, 2 , 145310; 3 , 145321. 4 , D and E

Figure 3 —Figured specimens of Iocrinus trentonensis from Walcott-Rust Quarry with anal tubes; all specimens from MCZ and coated with ammonium chloride. 1, 2 , Specimens with details of gaps between adjacent wing plates; 1 , side view of broken specimen with natural gaps, 145295, ×5.9; 2

Figure 5 —Drawings of figured specimens of Iocrinus trentonensis from the Walcott-Rust Quarry; all specimens from MCZ. 1–5 , Views of arm segments showing wide food grooves and large covering plates along one or both sides of food grooves; 1, 2 , tertibrachs from 145321 and 145310, ×11; 3, 4

subnodosus , and Iocrinus trentonensis . Data for food catching tube feet of the species, listed in order of length, diameter, and aspect ratio (length:width) of the taxa are: Iocrinus trentonensis 915 and 50.5 microns, 18.1; Cincinnaticrinus varibrachialus 575 and 39.5 microns, 14.6; Ectenocrinus

Figure 6 —Frequency graphs showing overlap of numbers of brachs between Iocrinus trentonensis and I. subcrassus . IBRR, IIBRR, and IIIBRR indicate primibrachs, secundibrachs, and tertibrachs

Figure 7 —Bivariate scatterplots comparing aboral cups and proximal brachs for Iocrinus trentonensis and I. subcrassus . IBRR, IIBRR, and IIIBRR refer to primibrachs, secundibrachs, and tertibrachs

Figure 8 —Frequency graphs illustrating multivariate differences between Iocrinus trentonensis and I. subcrassus as revealed by discriminant function scores and Q-scores for cluster significance tests

Figure 4 . Graphs showing size-frequency distributions and percent survivorship for Cincinnaticrinus varibrachialus , Ectenocrinus simplex , and Iocrinus trentonensis . The size-frequency plots are grouped into eight frequency classes so they can be compared with many of the figures in Brett

 =  Ectenocrinus simplex , 3 =  Cheirocystis anatiformis , 4 =  Iocrinus trentonensis , 5 =  Rhaphanocrinus subnodosus , 6 =  Merocrinus curtus , 7 =  Pycnocrinus argutus , 8 =  Calceocrinus barrandii , 9 =  Amygdalocystites florealis , 10 =  Dendrocrinus gregarius , 11 =  Merocrinus retractilis .

. Codes for species are: Amy  =  Amygdalocystites florealis , Chi  =  Cheirocystis anatiformis , Cin  =  Cincinnaticrinus varibrachialus , Ect  =  Ectenocrinus simplex , Ioc  =  Iocrinus trentonensis , Mer  =  Merocrinus curtus , Pyc  =  Pycnocrinus argutus , Rha  =  Rhaphanocrinus subnodosus

Figure 7 —Plot of mean food particle size versus standard deviation for food particle sizes. Numeric codes for species. 1–5, Open filter group. 1, Cupulocrinus crossmani . 2, Praecupulocrinus conjugans . 3, Eoparisocrinus crossmani Brower, 1994 . 4, Cupulocrinus levorsoni . 5, Iocrinus

Figure 5. Camera lucida drawings of Brechin crinoids: ( 1 ) Daedalocrinus bellevillensis Billings, 1883 , D-ray lateral view of partial calyx (compare to Figure 4.1 ), UMMP 74656; ( 2 ) Iocrinus trentonensis Walcott, 1883 , CD interray view of partial crown (compare to Figure 8.2 ), UMMP

- and quintibrachs with covering plates, paratype SUI 50875, ×13 and ×23. 10–12 , Iocrinus trentonensis Walcott, 1884 , disparid with slender arms having irregular isotomous arms similar to those of typical Ordovician cladids, C ray of figured specimen, MCZ 113637, ×1.65; distal brachs and quartibrachs of MCZ